288 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



transparent, and seem to have a i^upil and iris ; the nocturnal are, on the 

 contrary, dull and opaque.' 



Lebert expresses the same opinion,^ adding further that those which are 

 most convex and brightly colored, serve to see during daylight, and the 

 others, which are flatter and colorless, serve durfng the dusk. It occurred 

 to me to test this theory by making such division on the basis of habit, 

 as above referred to, and observe whether the spiders which incline to 

 nocturnal habits have the nocturnal or white eyes, and vice versa. Such 

 a comparison, extended to a few species, shows the following results : — 



Among our indigenous Orbweavers, those whose night habits are most 

 23ronounced, or whose ordinary habitat is dark or shaded places, proved to 

 have light colored eyes. For example, I rarely find Epeira strix 

 Night ui>on her web in daytime ; she comes out for prey in the early 

 ^^ J. evening or twilight, and remains quite persistently throughout 

 Byes ^'^^ *^^y ^^ ^^^' ^^^^^ ^^ curled leaf or in some convenient den. 



The eyes of this species have the entire rear row and the side 

 eyes of the front row a light gray color. The middle front eyes are of the 

 same color, but a darker shade. Meta menardii, which persistently inhab- 

 its shaded places, and whicli I have found in caves in central Pennsylva- 

 nia, has all its eyes a lighf pearl or gray color. The specimens of this 

 species examined were found in Sinking Spring Cave r^uite distant from 

 the mouth. The Ray spider I have alwa^^s found in ravines or well shailed 

 spots under the cover of ledges or foliage. Its eyes are all a light pearl, 

 the middle front eyes having a little darker shade. 



Turning to other tribes I found, for example, that the Medicinal spider 

 (Tegenaria medicinalis) has all its eyes yellow, with the excejition of the 

 small midfront pair, which are dark with a marginal ring of light color. 

 Its dwelling place is habitually cellars and dark corners. I have often 

 found it living quite in the shade. 



Clubiona palens, which lives within a silken tube and is frequently 

 found underneath stones, has pearly white eyes, tlie middle front being a 

 slightly darker shade. Tlie eyes of Agalena na^via are all a uniform bril- 

 liant yellow (amber), rather darker than Tegenaria medicinalis. This spi- 

 der inhabits a tube which expands into a sheeted web. She keeps habit- 

 ually on guard within the mouth of her tube, but sallies forth at all hours 

 of the day after the prey which drops or alights upon her web. She evi- 

 dently possesses good daj' sight. So far, therefore, one might say that the 

 conjecture that the white eyes are used for seeing in the dark, are nocturnal 

 eyes, in fact, is corroborated. 



lUit a further examination introduces facts which are in sA'ious conflict 

 with the theory. For example, Argiope cophinaria lives persistently in the 



' Siiiion, Histoire Naturelle des Araigiiees, page 35. 



' Die Spinnen der Sc-hweiz, page (i, (jucjted by Lubboik, " On Ants, Bees, and Wasps," 

 Linn. Soe. Jour., Veil. XX., 125. 



