94 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 97 
KEY TO THE GENERA 
1. Palpus approximately as long as third antennal segment and extending beyond 
oral margin, if at all, by a distance not greater than length of second antennal 
segment; vertex at least one-third head width___-_____-__--_---_------- 2 
Palpus usually 1.3 to 2 times length of third antennal segment and extending 
beyond oral margin by a distance usually twice or more the length of second 
antennal segment; if palpus is but little longer than third antennal segment, 
vertex less‘than one-fifth’ head“ widthlueet 2220. 22 See ee ee 4 
2. Prosternum bare; frontalia approximately as wide as a parafrontal; lateral 
postscutellar plates bare; tergites mainly shining dorsally________--_-_- 3 
Prosternum bristled at sides; frontalia approximately width of combined para- 
frontals; each lateral postscutellar plate with a tuft of setulae; tergites 
MOMmMOse dOLSaIly —2e +o. sees See ee ee ae 1. Proleskiomima 
8. Haustellum cylindrical, not noticeably constricted on apical half, at most 
three-fourths head height; outer verticals prominent; male without pro- 
clinate frontoorbitals and with elongated tarsal claws___--_-_ 2. Leskiella 
Haustellum strongly constricted on approximately penultimate fourth, at 
least almost head height; outer verticals absent or indistinguishable from 
postocular setulae; males and females alike with two proclinate frontoor- 
bitals and with short tarsal 'clawsi22 3222222 Swe ees 3. Leskiomima 
4. Costal spine strong; front noticeably flattened ; three proclinate frontoorbitals ; 
three frontals below antennal bases_____---_---_-_---_--~~ Spathipalpus 
Costal spine rudimentary; front at least slightly convex; at most 2 proclinate 
frontoorbitals, except as an abnormal condition; one or two frontals below 
LATENT ACS on Sn en te a Sees ae Te ee ee 5 
5. Vertex about one-third head width, that of male slightly narrower than that 
of female; male and female alike with two proclinate frontocrbitals and 
WMS Ob. Cla Wass aa fe NE 8 4. Dejeaniopalpus 
Vertex not more than two-sevenths, usually one-fourth to one-sixth head width, 
and much narrower in male than in female; male without frontoorbitals and 
WinlhiGioncated Clawss sess cena. a eee ee eee 5. Genea 
1. Genus PROLESKIOMIMA Townsend 
Proleskiomima TowNSEND, Rev. Ent., vol. 4, pp. 395-396, 1934; Manual of myiology, 
pt. 4, p. 65, 1936; pt. 9, pp. 234-235, 1939. 
Female (male unknown).—Head 0.6 as long and 1.25 as wide as 
high. Front flat in profile; vertex 0.4 head width; frontalia broad, 
about twice maximum width of a parafrontal; epistoma in clypeal 
plane; parafacial at base of antenna fully three times as wide as at 
narrowest part; facials approximately in clypeal plane, each with a 
few very short setulae and two or three short bristles near vibrissa; 
cheek 0.2 eye height. Haustellum in type specimen partly withdrawn, 
but apparently about half head height; straight, cylindrical, becoming 
somewhat smaller in diameter toward apex; labella small; palpus 
spatulate, slightly bowed, approximately as long as third antennal 
segment, with two or three outstanding setulae near apex below. Third 
antennal segment three times as long as second. Lateral postscutellar 
plates each with a tuft of short black hairs between halter and base of 
