PULMONARI^. 169 



taken. No sooner is one of them arrested there by the 

 hooks of its tarsi, than the Spider, some times placed in the 

 centre of his net, or at the bottom of his web, or at others lying 

 in ambush in a peculiar domicil situated near and in one of 

 the angles, rushes towards his victim and endeavours to pierce 

 him with his murderous dart, distilling into the wound a 

 prompt and mortal poison ; should the former resist too vigor- 

 ously, or should it be dangerous to the latter to approach it, 

 he retreats, waiting until it has either exhausted its powers 

 by struggling, or become more entangled in the net; but 

 should there be no cause of fear, he hastens to bind it by in- 

 volving the body in his silken threads, with which it is some- 

 times completely enveloped. 



Lister says that Spiders dart their threads in the same way 

 that the Porcupine darts his quills, with this difference, how- 

 ever, that in the latter, according to the popular belief, the 

 spines are detached from the body, whereas in the former, 

 these threads, though propelled to a considerable distance, 

 always remain connected with it. The possibility of this has 

 been denied. Be it as it may, we have seen threads issuing 

 from the mammillae of several Thomisi form straight lines, and 

 when the animals moved circularly, producing movable radii. 

 A second use to which this silk is applied by all female Ara- 

 neides, is in the construction of the sacs destined to contain 

 their eggs. The texture and form of these sacs are variously 

 modified, according to the habits of the race. They are 

 usually spheroidal ; some of them resemble a cap or tymbal, 

 others are placed on a pedicle, and some are claviform. They 

 are sometimes partially enveloped with foreign bodies, such 

 as earth, leaves, &c.; a finer material, or sort of tow or down, 

 frequently surrounds the eggs in their interior, where they 

 are free or agglutinated and more or less numerous. As they 

 are voracious animals, the males, in order to avoid a surprise 

 and to prevent themselves from falling victims to their pre- 

 mature desires, approach their females in the nuptial season, 

 with the greatest circumspection and mistrust. They cau- 

 tiously and repeatedly touch them, and frequently for a long 

 Vol. III.— W 



