316 THE BLOWFLIES OF NortH AMERICA 
the degree of pattern changing with the light position; second 
segment with a row of depressed marginal bristles which are 
longest laterally; all segments with considerable erect black 
hair. Fifth sternite (pl. 28, F) as illustrated. 
Genital segments black, relatively small, both segments with 
long erect black hair; inner and outer forceps of nearly same 
length, inner forceps with diverging inner margins. Internal 
anatomical details (pl. 28, E, F, and G) as illustrated. 
Female. Head width 17.9, length at antenna 8.2 and at 
vibrissa 8.7; height 13.7; eye height 8.4; bucca 0.65 eye height; 
frontale 0.5 width of front, reddish anteriorly and black posteri- 
orly; front at narrowest 0.35 of head width and 0.41 at lunule, 
the margins nearly parallel toward lunule where they diverge 
strongly, thinly covered with silver pollen, and with abundant 
short black hair outside frontal rows; frontal row consisting of 
eight to ten bristles, the rows not diverging anteriorly; outer 
vertical bristles two-thirds as long as inner, proclinate fronto- 
orbital bristles two; rarely an adventitious third; parafaciale 2.9 
in width opposite lunule; vibrissae set 3.4 apart; palpus 5.0 in 
length; third antennal segment 4.2 times as long as second. Wing 
with costal sections 2 to 6 in the proportion 95:75:150 :48 :12. 
Otherwise like male except for normal sexual differences. 
Length. 10-14 mm. 
Distribution. Holarctic. In North America from Alaska and 
Greenland southward to California and Virginia. Theoretically 
native to the Palearctic region this species has supposedly been 
widely distributed by commerce. It is probably much less 
widespread than generally believed. It is not common anywhere 
in North America but it is apparently most abundant in Alberta 
and along the Canadian-United States border. 
Townsend (1937, vol. 5, p. 142) considered vomitoria and 
vicina to be synonymous, with the latter a ‘‘color variant, with- 
out standing even as a restricted species, the color of the head 
and beard not being constant but dependent upon fluctuation 
of environmental factors.’’ The occurrence of variation in the 
coloration of these two species is not questioned, but there are 
few specimens which cannot be placed properly upon color 
alone. Furthermore, the differences found in the width of the 
front of the male offer a character that appears sufficiently stable 
to establish the distinctness of the two species. The differences 
indicated in the male aedeagus were questioned by Townsend 
(ibid.), who stated that those figured by Rohdendorf are illusory 
and not constant. I do not find them so. 
