ART. 4. REVISION OF THE FAMILY THEREVIDAE—COLE. 41 
The male is distinguished from haemorrhoidalis by having more of 
the frontal triangle shining black, the black running to the base of 
the antennae. On the male genitalia there are two clumps of short 
black spines at the tip of the hypandrium, one on each plate (fig. 2); 
the rest of the pile is pale yellowish or whitish and not largely black 
as in haemorrhoidalis; thus the two tufts of black bristles are very 
noticeable. As faras can be made out at present, the female is to be 
distinguished only by the difference in the extent of the silvery pollen 
on the frons, there being no silvery triangles on the lower corners of 
the frons, which in haemorrhoidalis reach up beyond the base of the 
antennae (fig. 43). These differences are slight but constant and do 
not break down in any of the series examined. The two species over- 
lap in their distribution over the Eastern States, but frontalis spreads 
much farther north and west. All of the Canadian specimens exam- 
ined belong to this species and not to the true hacmorrhoidalis. 
Larva.—About 25 mm. in length and very slender, not more than 
1.25 mm. wide at the thickest portion. White; the head small and 
dark brown. On the specimen there are no visible hairs on the head, 
but these have probably been rubbed off, as there are small marks 
resembling scars, situated much as in P. haemorrhoidalis, and the 
stigmatical spot is the same as in that species. The spiracles show 
plainly on the sides of nine of the abdominal segments, the last seg- 
ment ending in two small styliform bodies as usual. On most of the 
abdominal segments there are peculiar markings caused by curved 
rows of small round indentations, which are branched in a more or less 
characteristic manner. (Fig. 169.) 
Pupa.—The pupa is much like those of other known species of 
Psilocephala and Thereva. The arrangement of spines and tubercles 
does not seem to vary a great deal in the species examined. The 
general color is yellowish. Length about9mm. The two thorns on 
the head are quite long and sharply curved. (Fig. 170.) 
Type locality Holotype, male, and allotype, female, collected at 
Rochester, New York, July 4 and 24, 1914 (M. D. Leonard). 
Types.—In the Cornell University collection. 
Paratypes.—Male and female, No. 25930, U.S.N.M. 
Distribution.—Distribution according to 48 male and 72 female 
paratypes: 
Canada: Maniwak, Quebec, July 12; Montreal, August 11 (Beaulieu); 
Ottawa, Ontario, July 20 to August 14 (Beaulieu); Belleville, Ontario; 
Ottawa, Ontario, July 16 (A. Gibson); Ottawa, Ontario, June 26; 
Ottawa, Ontario, July 3 and August 7 (W. Metcalfe), [all Canad. coll.]; 
Jordan, Ontario, July 10 and 20 (H. Curran), [Cole]; Toronto, Ontario, 
July 18 (C. W. Johnson), [Cole]; Ontario, July 21 (Evans), at light 
(Canad. coll.]; Burlington, Ontario, June (H. C. Huckett), [Cornell]. 
Maine: Kennebunkport, July (G. H. Clapp), [U.S.N.M.]. 
