SYSTEMATIC ACCOUNT. 97 
Wings slightly yellowish, veins brown. Costal index about 4.6; fourth-vein index about 
1.3; 5x index about 0.9; 4c index about 0.7. 
Length body 3 mm.; wing 3.2 mm. 
Specimens examined: Ottawa, Canada (W. H. Harrington); Franconia 
(Mrs. Slosson), Hanover (C. W. Johnson), Bretton Woods (C. W. Johnson), 
New Hampshire; Chester, Massachusetts (C. W. Johnson); Ithaca, New 
York (R. C. Shannon); Pottstown, North Mountain, Pennsylvania (C. W. 
Johnson); Cabin John Bridge (types), Linnieville, Maryland (R. C. 
Shannon); District of Columbia (U. S. Nat. Mus. coll.); Dead Run, 
Glencarlyn, Virginia (R. C. Shannon); Georgia (U. 8. Nat. Mus. coll.). 
Drosophila virilis Sturtevant. 1916. Ann. Ent. Soc. America, 9, 330. 
o', 2. Arista with about five branches above and two below. Antenne brown, third 
joint dark opaque reddish-brown. Front over one-third width of head, wider above; dull 
coffee-brown, ocellar dot black. Second orbital one-third other two. Second oral bristle 
three-quarters length of first. Only one long bristle on each palpus. Carina broad, slightly 
sulcate, noselike; face somewhat shiny, brown. Cheeks yellowish brown; their greatest 
width over one-fourth greatest diameter of eyes. Eyes pilose. 
Acrostichal hairs in six rows; no prescutellars. Mesonotum and scutellum dark dull- 
brown. Pleurse and abdomen dull brown, somewhat darker. Legs pale brown. Apical 
and preapical bristles on first and second tibie, preapicals on third. 
Wings clear, veins brown. Costal index about 2.8; fourth-vein index about 1.8; 5x 
index about 1.2; 4c index about 0.9. 
Length body 2.8 mm.; wing 3.0 mm. 
Specimens examined: New York, New York (types); Terre Haute, 
Indiana (R. R. Hyde). I have also one specimen, collected at St. Elmo, 
near Chattanooga, Tennessee (W. 8. Adkins), that may belong here. The 
specimen is badly damaged, but agrees with this species so far as can be 
seen, except that the carina is not at all sulcate. It does not agree with 
any other species known to me. The New York record rests on a single 
pair bred from a pineapple exposed at Columbia University, in November 
1913, and descendants of this pair. This stock is still being kept in large 
numbers by Dr. C. W. Metz, who has used it 
extensively in genetic experiments. The Terre 
Haute record rests on one series taken by Dr. 
R. R. Hyde in a grocery store, and likewise 
kept as a stock. I have seen living material 
of this strain. It is identical with the New 
York stock. The species is very hardy and 
easily kept in the laboratory. This fact makes 
its great rarity in nature surprising. The fact 
that both of the certain records are based on 
material collected about buildings suggests 
that the species may be an introduced one. 
It may well have been described under an- 
other name from some other region, though 
I have been unable to find any description 1a. 48—Drosophila virilis. 
with which it can be identified. Head. 
The eggs have four filaments. The females 
ordinarily do not begin to lay until they are four or five days old. About 
three weeks are required for development. The mating habits, chromo- 
somes, and genetic experiments dealing with this species are described else- 
where in this paper. 
The small eyes and broad cheeks (fig. 48) make this species obviously 
distinct from such types as D. robusta (fig. 6) that resemble it superficially. 

