286 
Psyche 
[September 
NOTES ON AMERICAN NEMESTRINIDAE 
By J. Bequaert 
Department of Tropical Medicine, 
Harvard University Medical School 
Most of the following notes have been in manuscript for 
a number of years, pending their inclusion in a revision 
of the American representatives of this family. The recent 
discovery of some of these flies in Yucatan prompts their 
publication in the present form. 
Subfamily Nemestrininae 
The subfamily Nemestrininae should, in my opinion, 
comprise all nemestrinids with an elongate, slender, hard 
proboscis, the labium usually provided with narrow labella. 
All the North and Central American species belong to one 
genus, Neorhynchocephalus. 
Neorhynchoeephalus Lichtwardt 
Neorhynchocephalus Lichtwardt, 1909 (July), Deutsch. 
Ent. Zeitschr., p. 512 (based upon two species: Rhyn- 
chocephalus sackeni Williston, 1880, and R. volaticus 
Williston, 1883) ; 1910, Loc. cit., p. 592. 
Rhynchocephalus subgenus N emestrinopsis Cockerell, 1910 
(October), Bull. Amer. Mus. Nat. Hist., XXVIII, p. 
285 (type by original designation: Rhynchocephalus 
volaticus Williston, 1883). 
This genus, which is exclusively American, may be de- 
fined as follows : 
Medium-sized flies, densely pilose, often with narrow 
hair-bands on the abdomen; the integument black, dark 
brown, or reddish yellow. Head broad and short, flattened 
