No. 1.] SEXUAL SELECTION IN SPIDERS. 13 



known, are smaller and much more active in their habits. 

 Contrary to what we should expect on the theory, however, the 

 males are, as compared with the females, inconspicuous and 

 plainly colored ; the females being almost always strikingly 

 and often very brilliantly adorned with black, yellow, 

 red, blue and white. If it be objected that the Gastera- 

 canthidss do not entirely meet the point in question^ since 

 their colors have been developed as a warning of their inedi- 

 bility, there are scores of edible species among the web-build- 

 ing spiders which are brilliantly colored and, at the same time, 

 are very inactive ; as in the genera Epeira, Meta, Teiragnatha, 

 Theridium, Linyphia and others. 



Turning to the family Lycosidss, with its numei'ous species, 

 just the reverse appears, since it is among these vagabond or 

 wolf-spiders that we find the most vigorous species, ever run- 

 ning about and full of restless activity. We know a good deal 

 of their habits and of the courage of the females in defending 

 their young; but, contrary to what we should expect, this family 

 presents very little color development, dull grays, browns and 

 blacks prevailing. The Agelenidse are very active in their move- 

 ments, throwing themselves upon their prey with great vigor, 

 and depending upon their strength, and not upon web-lines, to 

 hold it, even when it is large and powerful. These spiders are 

 also dull colored. 



The spiders, then, seem well adapted to disprove the prop- 

 osition that there is a causal relation between vital activity and 

 color development, since in the sedentary groups, while many 

 of the species are plainly colored, there are nearly as many that 

 present the most beautiful tints ; and, on the other hand, some 

 of the wandering and very active groups are, for the most 

 part, clothed in sombre hues. 



Turning to the other question, how far have the females 

 had their color toned down, as compared with the males, for 

 purposes of protection during the nesting period ? If we ex- 

 amine the Attidse, where there are marked differences in the col- 

 oration of the sexes, we find that all the females remain under 



