The Common Spiders of the United States

Part 1

Transcriber's Notes at end of index.

$Bold words$ have been marked with dollar signs and italic words with underscores.

THE

COMMON SPIDERS

OF THE

UNITED STATES

By JAMES H. EMERTON

BOSTON, U.S.A., AND LONDON

GINN & COMPANY, PUBLISHERS

The Athenæum Press

ENTERED AT STATIONERS' HALL

COPYRIGHT, 1902, BY

JAMES H. EMERTON

ALL RIGHTS RESERVED

24.12

PREFACE

There are few books on the American spiders, and these are either large and expensive works or else special papers published by scientific societies, and so little known to the public. Since publishing my papers on the New England and Canadian spiders in the Transactions of the Connecticut Academy from 1882 to 1894, I have had frequent calls for a smaller and simpler book to meet the wants of readers who, without making a special study of the subject, want to know a little about spiders in general and especially those species that they often meet with. It is hoped this book will answer the purpose and help to lessen the prejudice against spiders, and lead to a more general acquaintance with them, like the popular knowledge of birds and butterflies. The characters used in the descriptions are, as far as possible, those that can be seen without microscopic examination and without much experience in the handling of small animals. The illustrations, which show the form and markings of every species, are from my own drawings and photographs, a large part of them made new for this book.

J. H. EMERTON.

APRIL, 1902.

CONTENTS

INTRODUCTION PAGE NUMBER AND NAMES OF SPIDERS vii ANATOMY viii SILK AND SPINNING ORGANS x COLORS AND MARKINGS xi HABITATS OF COMMON SPIDERS xii-xiv COBWEBS xvi CATCHING AND PRESERVING SPIDERS xvii THE DRASSIDÆ 1-21 CLUBIONA 15 THE DYSDERIDÆ 22 THE THOMISIDÆ 24-40 MISUMENA 25 XYSTICUS 30 PHILODROMUS 35 THE ATTIDÆ 41-66 THE LYCOSIDÆ 67-90 LYCOSA 68 PARDOSA 78 DOLOMEDES 85 OCYALE 88 OXYOPES 88 THE AGALENIDÆ 91-106 THE THERIDIDÆ 107-13 THERIDIUM 110 STEATODA 119 PHOLCUS 128 SCYTODES 131 THE LINYPHIADÆ 134-153 LINYPHIA 134 ERIGONE 148 THE EPEIRIDÆ 154-204 ROUND WEBS OF THE EPEIRIDÆ 155-159 SPECIES OF EPEIRA 160-181 THE THREE SPECIES OF THE GENUS ZILLA 184 ACROSOMA 188 ARGIOPE 192-198 TETRAGNATHA 198-204 THE CINIFLONIDÆ, OR CRIBELLATA 205-220 DICTYNA 205 AMAUROBIUS 213 ULOBORUS 216 HYPTIOTES 218 FILISTATA 220

INTRODUCTION

This book is designed to make the reader acquainted with the common spiders most likely to be found over a large part of the United States as far south as Georgia and as far west as the Rocky Mountains. Local collections show that in the neighborhood of any city in the country there are at least three or four hundred species of spiders; but few such collections have been made, and it is not yet possible to tell all the kinds of spiders that live in any particular place, or how far any species extends over the country. The species which are here described and figured are all of them well known and have been described in other books. Rare and doubtful species are omitted, though some of these may in time prove to be among the most common. A large number of spiders are too small to be easily seen, and most of these are omitted, only a few representative species being described. Spiders have, unfortunately, no common names, except such indefinite ones as "the garden spider," "the black spider," "the jumping spider," and the like. Even "tarantula" has become only a nickname for any large spider. The names of spiders, like those of other animals, have been given to them independently by different persons, so that many of them have more than one name, and the more common the spider the larger the number of names. In this book only one name is usually given to each species, and the name used is one that has been published with a description of the species in some other well-known book. Readers who are interested in the names of species and in comparing the classifications of different naturalists are referred to a "Catalogue of the Described Araneæ Of Temperate North America," by George Marx, in the Proceedings of the United States National Museum, 1890, which is a useful index to what has been published on American spiders.

The front half of a spider's body, called the cephalothorax, contains in one piece the head and thorax, the only outward division between them being shallow grooves from the middle of the back to the front legs. In the middle of the cephalothorax is usually a groove or depression, under which, inside, is a muscle that moves the sucking apparatus by which food is drawn into the mouth. At the sides of the thoracic part are four pairs of legs, and on the head part are a pair of palpi and a pair of mandibles. The legs have seven joints: (1) the coxa, the thick basal joint, having little motion; (2) the trochanter, a short joint moving very freely on the end of the coxa; (3) the femur, the largest joint of the leg, moving with the trochanter in all directions; (4) the patella, moving up and down on the end of the femur; (5) the tibia, joined closely to the patella and moving with it up and down; (6) the metatarsus; and (7) the tarsus, moving together on the end of the tibia. The palpi are like small legs and have one less joint than the walking legs. The mandibles are close together at the front of the head (fig. 2). They are two-jointed, the basal joint stout and the end joint or claw slender and sharp-pointed. The claw has near its point a small hole, which is the outlet of the poison gland. The poison kills or disables the insects which are captured by the spider. Its effect on the human skin varies in different persons; sometimes it has no effect at all; oftener it causes some soreness and itching like the stings of mosquitoes and bees, and cases have been known in which it caused serious inflammation which lasted a long time. Spiders seldom bite, and only in defense, the bites so commonly charged to them being often the work of other animals.

On the front of the head are the eyes, usually eight in number, differing in size and arrangement according to the kind of spider. The sight of spiders is distinct for only short distances. Spiders of middle size can see each other, and the insects which they eat, at a distance of four or five inches, but beyond that do not seem to see anything clearly. At the ends of the feet are two claws, curved and with teeth along the inner edge, and in many spiders there is a third shorter claw between them (fig. 212). The claws are sometimes surrounded by a brush of flattened hairs (figs. 104, 114). The basal joints of the palpi are flattened and have their inner edges extended forward so that they can be used as jaws to press or chew the food. These are called the maxillæ. Between the maxillæ is a small piece called the labium, and between the legs is a larger oval piece called the sternum.

The hinder half of the body, the abdomen, is connected with the cephalothorax by a narrow stem (fig. 1). It has at the hinder end the spinnerets, three pairs of appendages having at their ends a great number of microscopic tubes through which the thread is drawn out. When not in use the spinnerets are folded together, so that the smaller inner pair are concealed.

The thread of spiders resembles that spun by caterpillars in making their cocoons, and can be manufactured in the same way into silk cloth. The spider's thread is composed of a great number of finer threads passing from the body through separate tubes and uniting into one before they have time to dry. This can be seen by examining the attachments of spiders' threads to glass. All the spinning tubes are not alike, but on certain parts of the spinnerets are larger or differently shaped tubes, and these are the outlets of glands of different kinds in the spider's abdomen, and are used in making different kinds of threads for certain parts of the webs, nests, or cocoons.

In front of the spinnerets on the under side is a small opening to the tracheæ, or air-tubes (fig. 1). At the front of the abdomen on the under side is a transverse fold of the skin, at the ends of which are the openings of the air-sacs or lungs, and between them the opening of the reproductive organs (fig. 1). The latter is covered in females by an apparatus, sometimes large and complicated, called the epigynum. Its presence shows that the female is full grown. Young spiders do not have it. Male spiders have the ends of the palpi enlarged, and under the terminal joint what is known as the palpal organ, sometimes very complicated in shape. The presence of these organs shows that the male is full grown. Young males that have nearly reached maturity have the ends of the palpi simply enlarged. Male spiders almost always have the body smaller and the legs longer than females of the same species.

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