396 PECKHAM. [Vol. i. 



specimens of strix, labyrinthea, and insularis. All seemed 

 able to hear perfectly well without these organs. We also 

 found that the palpi play no essential part in the building of 

 the web, since all these spiders constructed normal webs after 

 their palpi were removed. This confirms, to some extent, the 

 conclusions of Plateau,^ though his further statement that 

 " these appendages are to be placed in the category of useless 

 organs " seems to be scarcely warranted. 



We made an effort to determine how far the first and second 

 pairs of legs subserve the sense of hearing, by removing them, 

 and noting the results. We first removed, at the coxae, the 

 two anterior legs of a female of E. insularis. She soon built 

 a good web, and when, two days later, the B fork was sounded 

 near her, she promptly threw up her second pair of legs in the 

 characteristic way. 



Some days later we caught a large female of A. riparia that 

 had lost her first pair of legs and also the left leg of the second 

 pair. She vv^as placed in the enclosed porch, and by the next 

 day had built a good web, which lacked, however, the zigzag 

 line down the centre, which is characteristic of the web of this 

 species. (Two other specimens of A. riparia that had lost 

 their palpi, also omitted the zigzag.) The remaining leg of 

 the second pair was then removed, leaving the spider with 

 only the posterior two pairs. She was now offered a fly, 

 which she quickly seized and devoured. After her repast the 

 B fork was sounded near her, when she attempted to lift the 

 third pair of legs, but only partly succeeded. Several trials gave 

 similar results. The fork was next held well behind her, when 

 she slowly turned toward the sound. 



So far we had experimented only upon orb-weavers. We 

 now used the tuning-fork with half-a-dozen species of different 

 groups, making ten or twelve trials with each spider. None of 

 them gave the least indication of hearing anything. These 

 unresponsive species were : Hcrpyllus biliheatiis and ccclesiasti- 

 cus Hentz, Pardosa pallida Emerton, Pirata mimitus Emerton, 

 Lycosa nigroventris Emerton, and Dolomedcs tcnebrusits Hentz, 

 It struck us as remarkable that, while all the Epeirids responded 

 promptly, being evidently alarmed by the sound of the tuning- 

 fork, the spiders that make no web, on the contrary, gave not 

 ' American Naturalist, April, 1887, p. 3S4. 



