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 Aporus. The genns 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 Pogonomyrmex; P. 
barbatus , so common everywhere else in the surrounding country, 
does not occur in the sand land where P occidentalism 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 
and can scarcely pierce one’s skin. The resemblance to the ant is 
