128 ZOOLOGY. 



take flies, those formed by the large and handsome species of Epeira {i)l. 

 77, iigs. 53, 59) are among the most regular. 



The cocoon in which the eggs of spiders are inclosed is carefully guarded. 

 Some species seat themselves over it as if in the act of incubation, some 

 place it in their retreats, some in their webs, and the wandering species 

 affix it to their abdomen. In this case, if it be forcibly removed, it is sought 

 for with great solicitude, and when found, carried off or re-affixed. 



Flies and other insects constitute the chief food of spiders, and they must 

 be taken living by the spider itself, or they will be generally rejected. Spiders 

 are capable of fasting several months, and they pass the winter without 

 food, being then torpid. They are eaten by various birds, reptiles, and 

 other animals, and some of the stinging Hymeiioptera fill the cells of their 

 young with them for the food of the latter, being endowed with the remark- 

 able instinct of disabling the spiders to such an extent as to render them 

 perfectly helpless, so* as to be unable to resist the young Hymenoptera, 

 whilst they have life enough to keep them in a fresh state as long as they 

 are wanted for food. 



The spiracles are situated near the base of the abdomen beneath, one or 

 two upon eacli side of the middle. AYhen there are but two spiracles, they 

 communicate with extremely thin laminated gills which have their extremities 

 directed towards the aperture, so that the air can be readily admitted to 

 them. When there are four spiracles, the two posterior ones communicate 

 with tracheae. The latter belong to the family Ifi/galidcB (considered a 

 section or sub-order by some authors, under the name of Tetrapneumones)^ 

 and containing the sub-families MygalhuB^ Atypinm^ and Dysderince. 

 Those with two spiracles have been named Dqmeumones. They constitute 

 the family Areneidm^ wnth the six sub-families : Areneince, Tlieridionince^ 

 Ei)cirina>^ Thomisina\ Lycosincc^ and Salticince. 



The species of Mygale {pi. 77, fig. 58) live in holes of their own con- 

 struction, some of which are closed by a trap-door, which renders them 

 difficult to find, and affords a protection to the ingenious constructor. The 

 trap-door is wider externally than internally, or slightly conical, and the 

 mouth of the aperture is formed so as to receive it with great exactness, 

 whilst the form is such as to prevent it from becoming fastened, as would 

 often be the case were it cylindrical. This door is made of about thirty 

 layers of silk and dirt, the layers being somewhat in the shape of small 

 brass weights, the different sizes of which lie one within the other. Upon 

 leaving or entering its burrow the lid closes after the spider by its own 

 weight, and when the animal is upon the outside it must be raised to allow 

 it to enter. The elasticity of the hinge is sufficient to close the aperture if 

 the lid be raised vertically, or drawn still further back ; and it is assisted by 

 the distribution of the earthy material, which is thickest towards the hinge, 

 and on this account less likely to be thrown backwards beyond its centre of 

 gravity. Near the margin of the inuer side of the lid, and opposite the 

 hinge, the Mygale forms a series of small holes to enable it to insert its 

 claws and jaws to hold it in place, in case of an attempt to raise the lid from 

 without ; and if a knife is inserted so as to run beneath the spider, and the 

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