ART. 11. GENUS MESEMBRINELLA GIGLIO-TOS—-ALDRICH. 1 
beginning at the tip of the auxiliary and filling the space in front of 
the second vein. The antennae are a little longer than in tibialis, 
reaching almost to the vibrissae; the bristles on the upper edge of the 
hind femur are longer and in a single row; the hind tibia is a little 
flattened and has the calcar almost at two-thirds its length, while in 
tibralis it is nearer the middle. 
Length, 10 mm. 
One male, Espirito Santo, Brazil, collector unknown, from Prof. 
O. A. Johannsen. 
Type.—Male, Cat. No. 25845, U.S.N.M. 
MESEMBRINELLA AENEIVENTRIS Wiedemann. 
Dexia aeneiventris WIEDEMANN, Auss. Zweifl. Ins., vol. 2, 1830, p. 376. 
Ochromyia nigrifrons Breor, Annales Soc. Ent. France, 1878, p. 39. 
Mesembrinella nigrifrons BrRavER, Sitzungsber. Kais. Akad. Wien, vol. 108, 
1899, p. 518. 
Mesembrinella aeneiventris Surcour, Revis. Musc. Test., 1919, p. 68, pl. 3, fig. 
5.—VILLENEUVE, Bull. Soc. Ent. France, 1920, p. 224. 
The type locality is ‘ Brazil,” and Bigot’s material was also from 
there. Brauer merely refers Bigot’s type to Mesembrinella. 
A male specimen from Peru, identified by Surcouf and mentioned 
by him in his revision, has been kindly sent me for study by Professor 
Bezzi. It is so nearly like my tibialis that I at first thought them 
the same. Having only the two males, one of each, the question 
can not be settled positively; however, there are at least two pretty 
fair distinctive characters, as indicated in the table. Aeneiventris 
has a large posthumeral bristle halfway between the presutural and 
the hindmost humeral and in the same line with them, which is 
absent in tibialis. The other posthumeral, present in both, is equi- 
distant from the presutural and the foremost of the anterior dorso- 
centrals, and considerably anterior to the line connecting them. The 
Peruvian specimen does not have the third posthumeral mentioned 
by Surcouf. There is a smallish but distinct flexor bristle beyond 
the middle of the middle tibia in tebialis, which is absent in aenei- 
ventris. The genitals are on the same plan in the two specimens, 
but the inner forceps are larger in aenewentris (in the proportion of 
17 to 14), and the outer are slightly broader and more rounded 
apically. I can detect no other differences. 
Surcouf did not see the type of aenewentris, nor that of nigrifrons, 
which he places as a synonym. 
MESEMBRINELLA FACIALIS, new species. 
Female.—Brownish yellow all over except the fourth abdominal 
segment and indistinct hind border of the third, running foward to 
a point in the median line, where the color is almost black, with no 
