350 THE AMERICAN NATURALIST. [VOL. XXXV. 
thickened costal margin near the middle of the wing, and three faint, oblique 
longitudinal veins. Costal vein bristly along its entire length. alteres 
about as long as the hind metatarsus, distinctly three-jointed. Abdomen 
with six segments, the basal ones longest. It is chitinized above and mem- 
branous beneath. Hypopygium large, exserted, asymmetrical. 
Described from numerous female and two male specimens collected at 
Austin, Texas, in the nests of Eciton cecum Latr. and Eciton schmitti 
Emery, from October to 
February, the males only 
in February. 
The head of Ecito- 
myia is much as in 
Commoptera, but is 
sharply angled at the 
posterio-lateral corners 
and longer on the ver- 
tex. The palpi are 
flattened and appear 
much thicker when 
seen from above. The 
eyes are considerably 
smaller than in Com- 
moptera. The thorax 
is much wider than 
long and has no scutel- 
lum, while the meta- 
thorax is wholly con- 
cealed in the basal part 
a, dorsal view; of the abdomen. The 
appendages upon the 
dorsum of the thorax in the female of this species do not seem 
to be homologous with the similarly placed ones in Termitoxenia. 
They approach more closely to wings, while those in Termi- 
toxenia are, in structure at least, like the halteres of Commop- 
tera. That these appendages are wings is proved by their 
insertion evidently anterior to the meso-metapleural suture, 
and still more positively by their structure, as the homology of 
the thoracic segments is somewhat obscure. They are strap- 
shaped, and not round in cross-section; the dorsal side is 
Fic. 10.— Ecitomyia wheeleri, n. Sp., ó. 
4, side view; c, hypopygium 
