Chapter Ii (p. 15), or Certain Generations of Virgin Females Are

wingless, for example aphids (pp. 18-19) and gall-flies (pp. 94-5). Insects may thus become secondarily wingless, that is to say be manifestly the offspring of winged parents, and such wingless forms may on the other hand give rise to offspring or descendants with well-developed wings. Frequently, as in the case of the aphids, many wingless generations intervene between two winged generations. A striking illustration of this fact is afforded by an aquatic bug, Velia currens, commonly to be seen skating over the surface of running water. The adults of Velia are nearly always wingless, but now and then the naturalist meets with a specimen provided with functional wings, the possession of which enables the insect to make its way to a fresh stream. Moreover there are whole orders of parasitic insects, such as the lice and fleas, which, showing clear affinity to orders of winged insects, are believed to be secondarily wingless. These orders are designated by Sharp 'Anapterygota.' And from the analogy of the periodic loss and recovery of wings in various generations of the same species, he has concluded that the gap between the exopterygote and the endopterygote method of development may have been bridged by an anapterygote condition; that the ancestors of those insects with complete transformations were the wingless descendants of primitive insects which grew their wings from visible external rudiments, and that in later times re-acquiring wings, they developed these organs in a new way, from inwardly directed rudiments or imaginal buds.

This theory of Sharp's is original, daring, and ingenious, but the loss and re-acquisition of wings which it presupposes is difficult to imagine in large groups during a prolonged evolutionary history, while the sudden appearance of a totally new mode of wing-growth in the offspring of wingless insects would be an extreme example of discontinuity in development.

On the whole the most probable suggestion which can be made as to the origin of 'complete' transformation in insects is that the instar in which wings were first visible externally became later and later in the course of the evolution of the more highly organised groups. In this way a gradual transition from the exopterygote to the endopterygote type of life-story is at least conceivable. It will be remembered that a may-fly (p. 33) undergoes a moult after acquiring functional wings, emerging into the air as a 'sub-imago.' In not a few endopterygote insects, the pupa shows more or less activity, swimming through water intermittently (gnats) or just before the imago has to emerge (caddis-flies); working its way out of the ground (crane-flies) or coming half-way out of its cocoon (many moths). The pupa of the higher insects almost certainly corresponds with the may-fly's sub-imago, and the facts just recalled as to remnants of pupal activity suggest that in the ancestors of endopterygote insects what is now the pupal instar was represented by an active nymphal or sub-imaginal stage, possibly indeed by more than one stage, as Packard and other writers have stated that pupae of bees and wasps undergo two or three moults before the final exposure of the imago. Such an early pupal instar has been defined as a 'pro-nymph' or a 'semi-pupa.' Examples have been given of the exceptional passive condition of the penultimate instar in Exopterygota. The instars preceding this presumably had originally outward wing-rudiments in all insect life-histories, and the endopterygote condition was attained by the postponement of the outward appearance of these to successively later stages. The leg and wing rudiments of the male coccid (pp. 20-1) beneath the cuticle of the second instar are strictly comparable to imaginal buds, and these are present in one instar of what is generally regarded as an exopterygote life-history. The first instar in all insects has no visible wing-rudiments, but when they grow outwardly from the body, they necessarily become covered with cuticle, so that they must be visible after the first moult. There is no supreme difficulty in supposing that the important change was for these early rudiments to become sunk into the body, so that the cuticle of the second, and, later, of the third and succeeding instars, showed no outward sign of their presence. This suggestion is confirmed by Heymons' (1896, 1907) observation of the occasional appearance of outward wing-rudiments on the thoracic segments of a mealworm, the larva of the beetle Tenebrio molitor, and by F. Silvestri's discovery (1905) of a 'pro-nymph' stage with short external wing-rudiments between the second larval and the pupal instars of the small ground-beetle Lebia scapularis. Whatever may be the exact explanation of these abnormalities, they show that in the life-story of the higher insects outward wing-rudiments may even yet appear before the pupal stage, confirming our belief that such appearance is an ancestral character. The inward growth of these wing-rudiments may well have been correlated with a difference in form between the newly-hatched insect and its parent. As this difference persisted until a constantly later stage, and the pre-imaginal instar became necessarily a stage for reconstruction, the present condition of complete metamorphosis in the more highly organised orders was finally attained.

To explain satisfactorily these complex life-stories is however admittedly a difficult task. The acquisition of wings is, as we have seen, a dominating feature in them all, but if we try to go yet a step farther back and speculate on the origin of wings in the most primitive exopterygote insects, the task becomes still more difficult. Many years ago Gegenbaur (1878) was struck by the correspondence of insect wings to the tracheal gills of may-fly larvae, which are carried on the abdominal segments somewhat as wings are on the thoracic segments. But Boerner has recently (1909) brought forward evidence that these abdominal gills really correspond serially with legs. Moreover Gegenbaur's theory suggests that the ancestral insects were aquatic, whereas the presence of tubes for breathing atmospheric air in well-nigh all members of the class, and the fact that aquatic adaptations, respiratory and otherwise, in insect-larvae are secondary force the student to regard the ancestral insects as terrestrial. It is indeed highly probable that insects had a common origin with aquatic Crustacea, but all the evidence points to the ancestors of insects having become breathers of atmospheric air before they acquired wings. How the wings arose, what function their precursors performed before they became capable of supporting flight, we can hardly even guess.

Our study of the life-story of insects, therefore, while it has taught us something of what is going on around us to-day, and has given us hints of the course of a few threads of that long life-story which runs through the ages, brings us face to face with the most instructive, if humbling fact that 'there are many more things of which we are ignorant.' The passage from creeping to flight, as the caterpillar becomes transformed into the butterfly, was a mystery to those who first observed it, and many of its aspects remain mysterious still. Perhaps the most striking result of the study of insect transformation is the appreciation of the divergent specialisation of larva and imago, and it is a suggestive thought that of the two the larva has in many cases diverged the more from the typical condition. The caterpillar crawling over the leaf, or the fly-grub swimming through the water, may thus be regarded as a creature preparing for a change to the true conditions of its life. It is a strange irony that the preparation is often far longer than the brief hours of achievement. But the light which research has thrown on the nature of these wonderful life-stories, the demonstration of the unseen presence and growth within the insect, during its time of preparation among strange surroundings, of the organs required for service in the coming life amid its native air, confirm surely the intuition of the old-time students, who saw in these changes, so familiar and yet so wonderful, a parable and a prophecy of the higher nature of man.

OUTLINE CLASSIFICATION OF INSECTS

Class INSECTA or HEXAPODA.

Sub-class A, APTERYGOTA.

Order 1. Thysanura (Bristle-tails). 2. Collembola (Spring-tails).

Sub-class B, EXOPTERYGOTA.

Order 1. Dermaptera (Earwigs). 2. Orthoptera (Cockroaches, Grasshoppers, Crickets). 3. Plecoptera (Stone-flies). 4. Isoptera (Termites or 'White Ants'). 5. Corrodentia (a) Copeognatha (Book-lice). (b) Mallophaga (Biting-lice). 6. Ephemeroptera (May-flies). 7. Odonata (Dragon-flies). 8. Thysanoptera (Thrips). 9. Hemiptera (a) Heteroptera (Bugs, Pond-skaters) (b) Homoptera (Cicads, 'Greenfly,' Scales). 10. Anoplura (Lice).

Sub-class C, ENDOPTERYGOTA.

Order 1. Neuroptera (Alder-flies, Ant-lions, Lacewings). 2. Coleoptera (Beetles). 3. Mecaptera (Scorpion-flies). 4. Trichoptera (Caddis-flies). 5. Lepidoptera (Moths and Butterflies). 6. Diptera (Two-winged flies) (a) Orthorrhapha (Crane-flies, Midges, Gnats) (b) Cyclorrhapha (Hover-flies, House-flies, Bot-flies, &c). 7. Siphonaptera (Fleas). 8. Hymenoptera (a) Symphyta (Saw-flies) (b) Apocrita (Gall-flies, Ichneumon-flies, Wasps, Bees, Ants).

TABLE OF GEOLOGICAL SYSTEMS

These names, given by geologists to the various divisions of rocks, as indicated by the fossils entombed in them, are arranged in 'descending' order, the more recent formations above, the more ancient below, as newer deposits necessarily lie over older beds.

CALNOZOIC OR TERTIARY GROUP.

Pleistocene. Pliocene. Miocene. Eocene.

MESOZOIC OR SECONDARY GROUP.

Cretaceous. Jurassic. Triassic.

PALAEOZOIC OR PRIMARY GROUP.

Permian. Carboniferous. Devonian. Silurian. Cambrian.

BIBLIOGRAPHY

The following list of some books and papers, referred to in this little volume or of especial service to the author in its preparation, is needless to say very far from exhaustive. To save space, titles are often abbreviated. Most of the works in the general list (A) contain extensive lists of literature on insects and their transformations, these should be consulted by the serious student.

A. GENERAL WORKS.

1909. C. Boerner. Die Verwandlungen der Insekten. Sitzb. d. Gesellsch. naturforsch. Freunde, Berlin.

1869. F. Brauer. Betrachtung ueber die Verwandlung der Insekten. Verhandl. der K.K. zool.-bot. Gesellschaft in Wien. XIX.

1899. G.H. Carpenter. Insects, their Structure and Life. London.

1859. C. Darwin. The Origin of Species. London.

1909. P. Deegener. Die Metamorphose der Insekten. Leipzig.

1906. J.W. Folsom. Entomology. London.

1878. C. Gegenbaur. Grundriss der Vergleichende Anatomie. Leipzig.

1906. A. Handlirsch. Die fossilen Insekten. Leipzig.

1904. L.F. Henneguy. Les Insectes. Paris.

1907. R. Heymons. Die verschiedenen Formen der Insectenmetamorphose. Ergebnisse der Zoologie. I.

1899. A. Lameere. La raison d'etre des Metamorphoses chez les Insectes. Ann. Soc. Entom. Bruxelles. XLIII.

1874. J. Lubbock. The Origin and Metamorphoses of Insects. London.

1895. L.C. Miall. (a) The Transformations of Insects. Nature. LIII.

1895. ---- (b) The Natural History of Aquatic Insects. London.

1908. ---- Injurious and Useful Insects. 2nd edition. London.

1839. G. Newport. Insects. Todd Cyclopaedia. II. London.

1898. A.S. Packard. Text book of Entomology. New York.

1734-42. R.A.F. de Reaumur. Memoires pour servir a l'Histoire naturelle et a l'anatomie des Insectes. Paris.

1895-8. D. Sharp. The Cambridge Natural History, V, VI. London.

1899. ---- Some points in the Classification of Insects. IV. Internat. Zoolog. Congress.

1902. ---- Insects in Encycl. Brit. 10th Edition, XXIX. London.

1910. ---- and G.H. Carpenter. Hexapoda in Encycl. Brit. 11th Edition. Cambridge.

1737. J. Swammerdam. Biblia Naturae. Leyden (incorporates works on Insects published during the author's lifetime 1669-75).

1909. F.V. Theobald. Insect Pests of Fruit. Wye.

B. SPECIAL WORKS.

1881. H. Adler. Ueber den Generationswechsel den Eichen-Gallwespen. Zeitsch. f. wissensch. Zoologie. XXXV.

1896. ---- and C.R. Straton. Alternating Generations. Oxford.

1902. J. Anglas. Nouvelles Observations sur les Metamorphoses Internes. Arch. d'Anat. Microscop. IV.

1911. E.E. Austen. Handbook of the Tsetse-Flies. London (Brit. Museum).

1909. F. Balfour-Browne. Life-History of Agrionid Dragonfly. Proc. Zool. Soc. Lond.

1893, &c. C.G. Barrett. Lepidoptera of the British Islands. London.

1890. H. Beauregard. Les Insectes Vesicants. Paris.

1909. C. Boerner. Die Tracheenkiemen der Ephemeriden. Zoolog. Anz. xxxiii.

1863. F. Brauer. Monographie der Oestriden. Wien.

1894. C. Brongniart. Recherches pour servir a l'histoire des Insectes fossiles des Temps Primaires. St Etienne.

1893. T.A. Chapman. Structure of Pupae of Heterocerous Lepidoptera. Trans. Entom. Soc. Lond.

1891. H. Dewitz. Das geschlossene Tracheensystem bei Insektenlarven. Zoolog. Anz. xiii.

1857-8. J.H. Fabre. L'Hypermetamorphose et les Moeurs des Meloides. Ann. Sci. Nat. (Zool.), (4). VII. IX.

1869. M. Ganin. Die Entwicklungsgeschichte bei den Insekten. Zeitsch. f. wissensch. Zoolog. xix.

1894. J. Gonin. La Metamorphose des Lepidopteres. Bull. Soc. Vaud. Sci. Nat. xxx.

1870. O. Grimm. Die ungeschechtliche Fortpflanzung einer Chironomus. Mem. Acad. Imper. St Petersbourg (7). xv.

1890. W. Hatchett-Jackson. Morphology of the Lepidoptera. Trans. Linn. Soc. (Zool.) Lond. (2). v.

1896. R. Heymons. Fluegelbildung bei der Larve von Tenebrio molitor. Sitzb. d, Gesellsch. Naturforsch. Freunde, Berlin.

1906. ---- Ueber die ersten Jugendformen von Machilis alternata. Ib.

1908. W. Kahle. Die Paedogenesis der Cecidomyiden. Zoologica. IV.

1913. V.L. Kellogg. Distribution and Species-forming of Ectoparasites. Amer. Naturalist. XLVII.

1887. A. Kowalevsky. Die nachembryonale Entwicklung der Musciden. Zeitsch. f. wissensch. Zool. XLV.

1904. O.H. Latter. Natural History of Common Animals (chaps. III, IV, V). Cambridge.

1890-95. B.T. Lowne. The Blowfly, 2 vols. London.

1863. J. Lubbock. Development of Chloeon. Trans. Linn. Soc. Lond. XXIII.

1762. P. Lyonet. Traite anatomique de la Chenille. Haag.

1669. M. Malpighi. De Bombyce. London.

1898. C.L. Marlatt. The periodical Cicada. Entom. Bull. 14, U.S. Dept. Agric.

1898. G.A.K. Marshall. Seasonal Dimorphism in Butterflies. Ann. Mag. Nat. Hist. (7). II.

1900. L.C. Miall and A.B. Hammond. The Harlequin Fly. Oxford.

1901-3. R. Newstead. Coccidae of the British Isles. London.

1877. J.A. Palmen. Zur Morphologie des Tracheensystems. Leipzig.

1891. E.B. Poulton. External Morphology of the Lepidopterous Pupa. Trans. Linn. Soc. Zool. (2). V.

1892. ---- Colour-relation between Lepidopterous Larvae &c. and their surroundings. Trans. Entom. Soc. Lond.

1880. C.V. Riley. Pupation of Butterflies. Proc. Amer. Assoc. XXVIII.

1902. E.D. Sanderson. Report of Entomologist. Delaware. U.S.A.

1885. E.O. Schmidt. Metamorphose und Anatomie des maennlichen Aspidiotus. Archiv f. Naturgeschichte. LI.

1885. S.H. Scudder. Insekten in Zittel's Paleontologie. II.

1907. A.J. Siltala. Die postembryonale Entwicklung der Trichopteren-Larven. Zoolog. Jahrb. Suppl. IX.

1905. F. Silvestri. Metamorfosi e Costumi della Lebia scapularis. Redia. II.

1900. J.B. Smith. The Apple Plant-louse. New Jersey Agric. Exp. Station Bull. 143.

1888. J. Van Rees. Die innere Metamorphose von Musca. Zoolog. Jahrb. Anat. III.

1911. K.W. Verhoeff. Ueber Felsenspringer, Machiloidea. Zoolog. Anz. XXXVIII.

1865. N. Wagner. Die viviparen Gallmueckenlarven. Zeitsch. f. wissensch. Zoolog. XV.

1901. E. Wasmann. Termitoxenia. Zeitsch. f. wissensch. Zoolog. LXX.

1864. A. Weismann. Die nachembryonale Entwicklung der Musciden. Zeitsch. f. wissensch. Zoolog. XIV.

1865. ---- Die Metamorphose von Corethra. Ib. XVI.

1876. ---- Studien zur Descendenz-Theorie. Leipzig. (English Translation by R. Meldola, London, 1882.)

INDEX

Abraxas grossulariata, 60, 83, 97-8

Adaptation of larvae, 57, 79, 114

Adephaga, 51

Adler, H., 94

Aeschnidae, 27, 29, 31

Agrionidae, 27, 28

Agrotis segetum, 98

Air-tubes, 2, 11, 23, 47, 70, 77, 87, 120

Alternation of generations, 17, 94

Ametabola, 11, 35

Anapterygota, 116

Anglas, J., 46

Ant-lions, 57

Ants, 64, 66

Aphidae, 17-20, 116

Aphis pomi, 18-19

Aphis-lion, 57

Apterygota, 41, 110

Aquatic insects, 23-34, 76-9, 120

Araschnia levana and var. prorsa, 103

Arctia caia, 98

Arctiadae, 59

Arthropoda, 9

Austen, E.E., 91

Avebury, Lord, see Lubbock, J.

Balfour-Browne, F., 28

Bark-beetles, 55

Barrett, C.G., 96, 99

Beauregard, H., 56

Bees, 40, 46, 64, 83

Beetles, 40, 50-7, 80, 107, 112-3, 119

Bell Moths, 62

Bird-lice, 108

Birth, 18, 91

Blatta orientalis, 15

Blister-beetles, 56

Blowfly or Bluebottle, 43, 44, 46, 67, 71-3, 93, 114

Boerner, C., 32, 120

Bot-flies, 73-4, 89, 91

Brain, 44

Brauer, F., 6, 52, 56, 67, 109

Bristle-tails, 11

Brongniart, C., 106

Butterflies, 1, 83, 95-6, 114

Cabbage-butterflies, 39, 41, 85, 100-1

Cabbage-fly, 73

Caddis-flies, 62-3, 86, 117

Cainozoic insects, 107

Calliphora, 43. See also Blowfly

Campodeiform larvae, 52, 56, 111

Carabidae, 52

Carboniferous insects, 107

Carpocapsa pomonella, 99-100

Carrion-beetles, 50

Caterpillar, 4, 36, 49, 58-62, 95-101, 109, 114

Cecidomyidae, 68-70, 90

Cerambycidae, 55

Cercopods, 12, 15

Chafers, 52

Chapman, T.A., 81, 84

Chironomus, 43, 77, 87, 91

Chloeon, 33

Chrysalis, 82. See also Pupa

Chrysomelidae, 53. See also Leaf-beetles

Chrysopa, 57

Cicads, 22, 93, 110

Classification, 122

Clearwing Moths, 62

Click-beetles, 52, 93

Clothes-moths, 62

Coccidae, 20, 110, 118

Coccinella, 113

Cockroaches, 11, 14, 15, 107, 115

Cocoons, 82

Codling Moth, 62, 99

Coleoptera, 50-6, 80, 112, 119

Collembola, 11

Complete transformation, 35, 107, 119. See also Endopterygota

Corethra, 43

Cossus, 38, 62, 82, 95

Crane-flies, 67, 70, 93, 117

Cremaster, 83

Crustacea, 7, 120

Culex, 43, 77, 86

Curculionidae, 55

Cuticle, 2, 9, 29, 37, 40, 50, 81, 87, 110

Cynipidae, 94. See also Gall-flies

Daddy-long-legs, 69-70

Darwin, C., 105

Deegener, P., 6, 114

Devonian insects, 107

Dewitz, H., 28

Digestive system, 10, 45-7

Diplosis pyrivora, 70

Diptera, 42, 64, 67-79, 81, 86-8, 91, 94, 107

Divergence between larva and imago, 110, 114, 121

Double-brooded Lepidoptera, 95, 100-4

Dragon-flies, 26-31, 107, 110

Drone-flies, 76

Duration of life, 34, 89, 92-3, 95

Dyticus, 51

Ecdysis, 10. See also Moult

Ectoderm, 9, 11, 47

Eggar Moths, 59, 89

Eggs, 6, 17-18, 26, 34, 65-7, 71, 90, 94-5, 97

Elateridae, 52

Endopterygota, 41, 49, 108, 112, 115-6

Ephemeroptera, 24. See also May-flies

Epidermis, 9, 40

Eristalis, 76

Eruciform larvae, 56, 58-70, 111

Evolution, 16, 103, 105-21

Exopterygota, 41, 108, 115-6, 118

Exoskeleton, 9

Fabre, J.H., 56

Fat-body, 47

Feeding-period, 27, 32, 36, 89, 111

Feelers, 1, 4, 42, 71

Fleas, 116

Fore-gut, 47

Free pupa, 80

Gall-flies, 64-6, 94, 115

Gall-midges, 68-70, 90

Ganin, M., 66

Gastrophilus equi, 73-4

Gegenbaur, C., 120

Geological history, 106-8, 123

Geometridae, 59

Gills, 24, 27, 32, 78, 87, 114, 120

Glossinia, 91

Glow-worm, 50, 113

Gnats, 43, 77, 86

Goat Moth, 38, 62, 82, 95

Gonin, J., 38, 41

Grasshoppers, 11, 14, 15

Grimm, O., 90

Ground-beetles, 52, 112

Growth, 9

Grub, 63-70. See also Caterpillar, Larva

Hairs, 59, 82, 98

Hammond, A.R., 43, 77, 87

Handlirsch, A., 106

Harvey, William, 7

Hatchett-Jackson, W., 83

Hawk Moths, 60

Heart, 45

Helodes, 50

Hemerobius, 57

Hemimetabola, 35

Hemiptera, 17, 110

Henneguy, L.F., 45, 48

Heymons, R., 6, 11, 119

Hibernation. See Wintering stages

Hind-gut, 47

Hippoboscidae, 91

Histogenesis and Histolysis, 48

Holometabola, 35

House-fly, 67, 71, 73

Hover-flies, 74-6

Hymenoptera, 58, 64, 94, 107

Hypermetamorphosis, 56

Hypoderma bovis, 73-5

Hypodermis, 9

Ichneumon-flies, 64, 66, 82

Imaginal buds or discs, 34-48, 114, 117-8

Imago, 24, 34, 114

Instar, 13, 33, 56, 117-9

Jaws of imago and larva, 2, 4, 5, 32, 42, 89

Jurassic insects, 107

Kahle, W., 90

Kellogg, V.L., 108

Kowalevsky, A., 46

Labium, 2, 27

Lacewing-flies, 57, 107

Ladybirds, 113

Lameere, A., 111

Lampyris, 113

Larva, 4, 22, 26-7, 32, 49-79, 110-15

Larval reproduction, 90

Lasiocampidae, 59, 89

Latter, O.H., 28

Leaf-beetles, 53, 83, 92-3, 113

Lebia scapularis, 119

Lepidoptera, 1, 36, 38, 49, 58, 81, 95-104, 107

Libellulidae, 27

Lice, 116

Lipeurus, 108

Longhorn Beetles, 55

Looper caterpillars, 59, 61

Lowne, B.T., 42

Lubbock, J., 6, 32

Lymantriidae, 90

Lyonet, P., 38

Machilis, 11

Maggot, 44, 67, 71-6, 109, 114

Magpie Moth, 60, 82, 97-8

Mallophaga, 108

Mandibles, 4, 17, 26, 58, 67, 86

Mangel-fly, 73

Marlatt, C.L., 93

Marshall, G.A.K., 104

Maxillae, 2, 17, 37, 42

May-flies, 31-4, 107, 110, 117, 120

Meloidae, 56

Mesozoic insects, 107

Metabola, 35

Metamorphosis (in general), 6, 109; (degrees of in insects) 8, 35, 109, 117-19

Miall, L.C., 6, 28, 33, 43, 77, 78, 87, 97, 113

Mosquito. See Culex, Gnats

Moths, 1, 58-62, 84, 95-100, 117

Moult, 10, 32, 36, 41

Musca domestica, 71

Muscidae, 44

Muscles, 47

Nervous system, 44-5

Neuroptera, 57, 80, 112

Newport, G., 41, 44

Noctuidae, 60, 98

Nymph, 15, 28, 33

Oak-apples, 94

Obtect pupa, 81

Odonata, 24. See also Dragon-flies

Oestrus ovis, 91

Oil-beetles, 56, 112

Orgyia antiqua, 96-7

Orthoptera, 17, 35, 110

Owl Moths, 60, 98

Packard, A.S., 56, 118

Paedogenesis. See Larval reproduction

Painted Lady Butterfly, 96

Palaeozoic insects, 107

Palmen, J.A., 25

Parasitic insects, 73-4, 108, 116

Parental care, 64-6

Parthenogenesis, 18

Partial transformation, 35, 37

Perla, 24

Permian insects, 107

Phagocytes, 48

Phyllodecta, 53, 113

Phyllotreta, 53

Pieris brassicae, 39, 41, 85, 100

Pieris napi and var. bryoniae, 102-3

Platygaster, 66

Plecoptera, 24. See also Stone-flies

Pompilidae, 66-7

Poulton, E.B., 61, 82, 109

Precis, 104

Proctotrypidae, 66

Pro-legs, 4, 58-9, 84, 114

Pro-nymph, 118, 119

Protective coloration, 60-1

Psylliodes chrysocephala, 54

Ptinidae, 54

Pupa, 4, 37, 40, 79-88, 114, 117

Puparium, 88

Pupipara, 91

Pyrameis cardui, 96

Rat-tailed maggot, 76

Reaumur, R.A.F. de, 8, 28, 33, 41

Reproductive larvae, 90; pupae, 91

Reproductive organs, 45

Rhabdophaga heterobia, 70

Riley, C.V., 83

Sanderson, E.D., 17

Sand-midges, 78

Sarcophaga, 91

Saw-flies, 58-9

Scale-insects, 20. See also Coccidae

Scarabaeidae, 52

Schmidt, E.O., 21

Scolytidae, 55

Scudder, S.H., 106

Seasonal changes, 89-104

Seasonal dimorphism, 102

Semi-pupa, 118

Sesiidae, 62

Sexual differences, 15, 20-1, 90

Sharp, D., 13, 36, 40, 115

Silk-spinning, 58, 62-3, 82

Silkworms, 82

Silpha, 50

Siltala, A.J., 63

Silvestri, F., 119

Simulium, 78, 87

Smith, J.B., 17

Sphegidae, 66-7

Sphingidae, 60

Spinneret, 58

Spiracles, 2, 23, 70, 72, 77, 86, 87

Spring-tails, 11

Stone-flies, 24, 107, 110

Sub-imago, 33, 117

Sucking insects, 17

Swammerdam, J., 33

Syrphus, 74-6

Tachininae, 73, 91

Tenebrio molitor, 119

Termitoxeniidae, 92

Theobald, F.V., 100

Thysanura, 11

Tiger Moths, 59, 82, 98

Timber-beetles, 54

Tineidae, 62

Tipulidae, 70

Tortoiseshell Butterfly, 45, 95

Tortricidae, 62

Tracheal system. See Air-tubes, Spiracles

Transformation. See Metamorphosis

Triassic insects, 107

Trichocera, 70

Trichoptera, 62-3, 76, 80, 86

Tsetse Flies, 91

Turnip-fly, 53, 92, 94

Turnip Moth, 98-9

Tussock Moths, 90, 97

Vanessa urticae, 45, 95

Van Rees, J., 42

Vapourer Moth, 96-7, 115

Velia currens, 116

Verhoeff, K.W., 11

Vermiculiform larvae, 67, 71-6, 111

Virgin stem-mothers, 18

Viviparous reproduction. See Birth

Wagner, N., 90

Warble-fly, 73-4, 89, 108

Warning coloration, 60

Wasmann, E., 92

Wasps, 46, 64, 66-7, 83

Water-insects. See Aquatic insects

Weevils, 55

Weismann, A., 38, 42, 102

White Butterflies, 41, 83, 85, 100-3

Willow-beetles, 53

Wingless insects, 15, 18, 20, 96, 115

Wing-rudiments, 13, 18, 20, 22, 24, 28, 33, 36-8, 40, 111, 115, 117-19

Wings, 1, 14, 115, 119-20

Winter broods, 102-3

Wintering stages, 93-101

Wireworms, 52, 93

Wood-wasps, 65

CAMBRIDGE: PRINTED BY JOHN CLAY, M.A. AT THE UNIVERSITY PRESS

THE CAMBRIDGE MANUALS OF SCIENCE AND LITERATURE

Published by the Cambridge University Press

GENERAL EDITORS P. GILES, Litt.D. Master of Emmanuel College and A.C. SEWARD, M.A., F.R.S. Professor of Botany in the University of Cambridge

70 VOLUMES NOW READY

HISTORY AND ARCHAEOLOGY

Ancient Assyria. By Rev. C.H.W. Johns, Litt.D. Ancient Babylonia. By Rev. C.H.W. Johns, Litt.D.

A History of Civilization in Palestine. By Prof. R.A.S. Macalister, M.A., F.S.A.

China and the Manchus. By Prof. H.A. Giles, LL.D.

The Civilization of Ancient Mexico. By Lewis Spence.

The Vikings. By Prof. Allen Mawer, M.A.

New Zealand. By the Hon. Sir Robert Stout, K.C.M.G., LL.D., and J. Logan Stout, LL.B. (N.Z.).

The Ground Plan of the English Parish Church. By A. Hamilton Thompson, M.A., F.S.A.

The Historical Growth of the English Parish Church. By A. Hamilton Thompson, M.A., F.S.A.

English Monasteries. By A.H. Thompson, M.A., F.S.A.

Brasses. By J.S.M. Ward, B.A., F.R.Hist.S.

Ancient Stained and Painted Glass. By F.S. Eden.

ECONOMICS

Co-partnership in Industry. By C.R. Fay, M.A.

Cash and Credit. By D.A. Barker.

The Theory of Money. By D.A. Barker.

LITERARY HISTORY

The Early Religious Poetry of the Hebrews. By the Rev. E.G. King, D.D.

The Early Religious Poetry of Persia. By the Rev. Prof. J. Hope Moulton, D.D., D.Theol. (Berlin).

The History of the English Bible. By John Brown, D.D.

English Dialects from the Eighth Century to the Present Day. By W.W. Skeat, Litt.D., D.C.L., F.B.A.

King Arthur in History and Legend. By Prof. W. Lewis Jones, M.A.

The Icelandic Sagas. By W.A. Craigie, LL.D.

Greek Tragedy. By J.T. Sheppard, M.A.

The Ballad in Literature. By T.F. Henderson.

Goethe and the Twentieth Century. By Prof. J.G. Robertson, M.A., Ph.D.

The Troubadours. By the Rev. H.J. Chaytor, M.A.

Mysticism in English Literature. By Miss C.F.E. Spurgeon.

PHILOSOPHY AND RELIGION

The Idea of God in Early Religions. By Dr F.B. Jevons.

Comparative Religion. By Dr F.B. Jevons.

Plato: Moral and Political Ideals. By Mrs A.M. Adam.

The Moral Life and Moral Worth. By Prof. Sorley, Litt.D.

The English Puritans. By John Brown, D.D.

An Historical Account of the Rise and Development of Presbyterianism in Scotland. By the Rt Hon. the Lord Balfour of Burleigh, K.T., G.C.M.G.

Methodism. By Rev. H.B. Workman, D.Lit.

EDUCATION

Life in the Medieval University. By R.S. Rait, M.A.

LAW

The Administration of Justice in Criminal Matters (in England and Wales). By G. Glover Alexander, M.A., LL.M.

BIOLOGY

The Coming of Evolution. By Prof. J.W. Judd, C.B., F.R.S.

Heredity in the Light of Recent Research. By L. Doncaster, M.A.

Primitive Animals. By Geoffrey Smith, M.A.

The Individual in the Animal Kingdom. By J.S. Huxley, B.A.

Life in the Sea. By James Johnstone, B.Sc.

The Migration of Birds. By T.A. Coward.

Spiders. By C. Warburton, M.A.

Bees and Wasps. By O.H. Latter, M.A.

House Flies. By C.G. Hewitt, D.Sc.

Earthworms and their Allies. By F.E. Beddard, F.R.S.

The Wanderings of Animals. By H.F. Gadow, F.R.S.

ANTHROPOLOGY

The Wanderings of Peoples. By Dr A.C. Haddon, F.R.S.

Prehistoric Man. By Dr W.L.H. Duckworth.

GEOLOGY

Rocks and their Origins. By Prof. Grenville A.J. Cole.

The Work of Rain and Rivers. By T.G. Bonney, Sc.D.

The Natural History of Coal. By Dr E.A. Newell Arber.

The Natural History of Clay. By Alfred B. Searle.

The Origin of Earthquakes. By C. Davison, Sc.D., F.G.S.

Submerged Forests. By Clement Reid, F.R.S.

BOTANY

Plant-Animals: a Study in Symbiosis. By Prof. F.W. Keeble.

Plant-Life on Land. By Prof. F.O. Bower, Sc.D., F.R.S.

Links with the Past in the Plant-World. By Prof. A.C. Seward.

PHYSICS

The Earth. By Prof. J.H. Poynting, F.R.S.

The Atmosphere. By A.J. Berry, M.A.

Beyond the Atom. By John Cox, M.A.

The Physical Basis of Music. By A. Wood, M.A.

PSYCHOLOGY

An Introduction to Experimental Psychology. By Dr C.S. Myers.

The Psychology of Insanity. By Bernard Hart, M.D.

INDUSTRIAL AND MECHANICAL SCIENCE

The Modern Locomotive. By C. Edgar Allen, A.M.I.Mech.E.

The Modern Warship. By E.L. Attwood.

Aerial Locomotion. By E.H. Harper, M.A., and Allan E. Ferguson, B.Sc.

Electricity in Locomotion. By A.G. Whyte, B.Sc.

Wireless Telegraphy. By Prof. C.L. Fortescue, M.A.

The Story of a Loaf of Bread. By Prof. T.B. Wood, M.A.

Brewing. By A. Chaston Chapman, F.I.C.

SOME VOLUMES IN PREPARATION

HISTORY AND ARCHAEOLOGY

The Aryans. By Prof. M. Winternitz.

Ancient India. By Prof. E.J. Rapson, M.A.

The Peoples of India. By J.D. Anderson, M.A.

The Balkan Peoples. By J.D. Bourchier.

Canada of the present day. By C.G. Hewitt, D.Sc.

The Evolution of Japan. By Prof. J.H. Longford.

The West Indies. By Sir Daniel Morris, K.C.M.G.

The Royal Navy. By John Leyland.

Gypsies. By John Sampson.

A Grammar of Heraldry. By W.H. St John Hope, Litt.D.

Celtic Art. By Joseph Anderson, LL.D.

ECONOMICS

Women's Work. By Miss Constance Smith.

LITERARY HISTORY

Early Indian Poetry. By A.A. Macdonell.

The Book. By H.G. Aldis, M.A.

Pantomime. By D.L. Murray.

Folk Song and Dance. By Miss Neal and F. Kidson.

PHYSICS

The Natural Sources of Energy. By Prof. A.H. Gibson, D.Sc.

The Sun. By Prof. R.A. Sampson.

Roentgen Rays. By Prof. W.H. Bragg, F.R.S.

BIOLOGY

The Life-story of Insects. By Prof. G.H. Carpenter.

The Flea. By H. Russell.

Pearls. By Prof. W.J. Dakin.

GEOLOGY

Soil Fertility. By E.J. Russell, D.Sc.

Coast Erosion. By Prof. T.J. Jehu.

INDUSTRIAL AND MECHANICAL SCIENCE

Coal Mining. By T.C. Cantrill.

Leather. By Prof. H.R. Procter.

Cambridge University Press C.F. Clay, Manager London: Fetter Lane, E.C. Edinburgh: 100, Princes Street