VI. AGENIA, THE AMPUTATOR OF SPIDERS' LEGS. 



(a) Agenia, sp. NOV. and Agenia Accepta, Cress., Two Dig- 

 gers. 



The species of Agenia are the most agile of all wasps not even 

 excepting those of Pompilus and Aponis. The genus is unique in 

 that its members, I believe without exception, have the habit of 

 cutting off their victim's legs. I have gotten glimpses of the do- 

 ings of four species of Agenia ; the two species first considered dig 

 holes in the ground for their nests ; the other species, which are con- 

 sidered separately below, build elliptical cells of mud in which to 

 rear their young. Yet, though their nest-building habits differ so 

 widely, their general appearance and their behavior when abroad in 

 daylight make the genus easy of recognition. 



Agenia (sp. nov.) and Agenia accepta are very closely related 

 both as to habits and structural characters. The latter is half 

 again as large as the former, is darker in color and has clouded 

 wings. Both species have made a strong impression on my mind 

 because of their striking resemblance to the Texas red ant, Pogo- 

 nomyrmex. The new and undescribed species I have seen only in 

 the sandy woods on the river bank below Austin; A. accepta only 

 on the limestone hills in and about the city. The same fact of 

 distribution obtains for the common species of Pogonomyrmexj P. 

 barhatvs, so common everywhere else in the surrounding country, 

 does not occur in the sand land where Poccidenialis, var. Comanche, 

 with its disc-shaped mounds, is very common. These two species 

 of ants differ markedly in color and somewhat in size, Comanche 

 being the smaller and of a lighter hue. The same differences 

 exactly exist between Agenia sp. nov, and accepta, the former, the 

 smaller and lighter species, occurring only in the sandy tract above 

 mentioned. While this may be a mere coincidence it is worth 

 stating that most of the individuals which I have observed, were 

 either near or in the midst of a lot of red ants, which they resemble 

 respectively in size and color. Whether this be a real case of mim- 

 icry or not, I would not say. But there is no doubt that the pro- 

 tection afforded is considerable as the sting of the red ants is very 

 formidable and a thing to be dreaded, while that of Agenia is weak 



