ADDITIONAL OBSERVATIONS ON SEXUAL SELEC- 

 TION IN SPIDERS OF THE FAMILY ATTID^. 



GEORGE \V. AND ELIZABETH G. PECKIIAM. 



Ill the species of Attidse whose mating Iiabits we have 

 heretofore described, the adornments displayed by the male in 

 courtship have consisted of bright color on the cephalothorax 

 or abdomen, colored hairs on the clypeus, tufts or ridges of hair 

 over the face, modifications of the color or form of the first pair- 

 of legs, or modifications of the falces. We have had for some 

 time in our collection three species, all belonging to the same 

 genus, whose males showed a peculiar enlargement of the third 

 leg; thus in Habrocestum peregrinum the patella is enlarged 

 and somewhat triangular in shape, with an apophysis, of vari- 

 able length, projecting over the tibia, while the anterior face of 

 the patella has a black spot on a white ground. The third leg 

 of the male of Habrocestum coecatum has a similar, but less 

 striking, enlargement of the patella ; and in an as yet un- 

 described species, Habrocestum liowardii, the patella has the 

 same modification. 



The general appearance of this structure, together with the 

 fact that it was limited to the males, and was very variable, sug- 

 gested that it was one of those sexual adornments which are 

 useful in gaining the favor of the female. Had it occurred on 

 the first leg we should have felt reasonably sure that this was 

 its function ; but it seemed improbable that a modification of 

 the third leg could be displayed with advantage during court- 

 ship, and we were therefore considerably in doubt as to its 

 meaning. 



On the first day of June of the present year we were so 

 fortunate as to discover on a hot, stony hillside (on ground, by 

 the way, that we had worked industriously for ten years) large 

 numbers of males and females of a new species of Habrocestum, 

 having a modification of the third leg (Fig. 1) very similar to that 



