UOI.OK AND THK COLOR SENSE. 337 



But confusing elements do not stop here. Any one who is familiar with 

 our ordinary cellar spider fauna must have observed among thorn a strong 

 tendency to black or dark colons. The most common cellar spider in the 

 neighborhood of Philadelphia is probably the Tubeweavcr Tegenaria mc- 

 dicinalis. It is a quite dark lead color, which is as near black as any of 

 our indigenous spiders. So also Agalena naavia, when it nests in dark 

 places, as it often does, seems to me to add to the somewhat sombre colors 

 which it bears in arboreal and sunny sites, several additional tints of 

 darkness. 



It should be 'noted that in the case of the Tm-ret spider of Coffin's 

 Beach a large portion of the year must be spent in a torpid condition 

 by such individuals as survive the winter, which is severe and long in 

 that vicinity. On the other hand, the white spiders of Mammoth Cave 

 live in a uniform and pleasantly warm temperature. The same, to some ex- 

 tent, is true of the Medicinal spider, which is kept reasonably warm when 

 living in our cellars and other unfrequented places in human habitations, 

 but, unlike the Mammoth Cave Anthrobias, are black. Thus similar con- 

 ditions of temperature, as well as of light, appear in these cases to issue 

 in opposite conditions of color. 



V. 



I have already considered the theory of Pockliam that the bright orna- 

 mentation of the male Saltigrade spider serves to attract the attention of 

 the female, and to secure him her favor in preference to duller 

 Utrt • "°^^^'°*^^ rivals. In the case of Orbweavers, where the conditions 

 Matinff. ^^''^ reversed and the female is the more highly ornamented, we 

 may suppose that the point of utility is also reversed, and the 

 brighter colors of the female serve to attract to her the attention of the 

 male. In the case of Orbweavers and Lineweavers, there would seem to be 

 some necessity for this, inasmuch as the females for the most part occupy 

 the centre of their webs, which are often of considerable size, and thus 

 they would require to be marked in such wise that the vagrant male on 

 his courtship excursions could discern his mate at the distance of at least 

 several inches. It seems not an overstrained supposition that both the in- 

 creased size and excessive coloration of the female would make her a 

 more conspicuous object and thus facilitate the union of the two sexes. 



Again, in a large number of species which are influenced by what we 

 might call mimetic harmony, and to which allusion has already been 

 made, we can readily see how highly useful the general resem- 

 Harmony ^''^"^'^ "^ environment would be in protecting spiders from vari- 

 ous enemies. All the Wanderers, and some of the Sedentary 

 spiders, appear to be subject to those inlluences which harmonize their color 

 with the surroundings of their daily life. This subject may be more fully 

 considered in the chapter on Mimicry, but it has been necessary to allude 



