SUBFAMILY CALLIPHORINAE 309 
bristles two; mesothoracie spiracle with bright orange hair; meta- 
thoracic spiracle brown; squamopleuron with dark brown pubes- 
cence; preparapteron orange; other sclerites at wing-base dark 
brown. 
Wing with preepaulet, basicosta, and subcostal sclerite usually 
bright orange; costal segments 2 to 6 in the proportion 
89 :60 :126 :45 :10. 
Legs with bristling as in vomitoria. 
Abdomen blue, faintly metallic, whitish pollinose, tessellated; 
first segment nearly black; second segment with marginal row of 
short bristles which are longer and stronger laterally. 
Genital segments black, strongly setose above, the setae black; 
outer forceps long, margins parallel, the tips rounded. Internal 
anatomical features (pl. 28, C and D) as illustrated. 
Female. Head height 12.4; eye height 8.2; bucca 0.49 eye 
height; length at antenna 7.2 and at vibrissa 8.2; parafaciale op- 
posite lunule 0.82 the distance between the vibrissae; width 16.4; 
front at vertex (which is narrowest) 0.38 head width, 0.40 at 
lunule; third antennal segment 4.7 times as long as second; 
palpus 5.0; distance between vibrissae 3.3. Wing with costal 
sections 2 to 6 in the proportions 94:65:140:45:10. Otherwise 
similar to male except for normal sexual differences. 
Length. 6-12 mm. 
There is often considerable variation in the intensity of the 
orange color in this species. The anterior half of the bucea is 
most often orange, as are the preepaulet and the basicosta. But 
the bueca may sometimes be mahogany red, particularly in 
specimens from the far north. The basicosta is nearly always 
orange although a few specimens among those studied have both 
the preepaulet and the basicosta orange brown. Male specimens 
obviously differ from vomitoria and terrae-novae in the width 
of the front at the narrowest, but dark females of vicina are 
difficult to separate from those two species, although few speci- 
mens of vomitoria lack the obvious tawny-red hair on the buceca 
and this is nearly always lacking in vicina. 
Distribution. Holarctic. In North America, vicina is fairly 
eommon from Mexico City, Mexico, to Alaska, but it is most 
abundant from Virginia and Oklahoma northward into southern 
Canada. It is especially abundant in the middle-western part 
of the United States. There it is one of the first blowflies to 
appear in the spring and it is probably the most abundant blow- 
fly in this area during March and early April. Although a few 
specimens may be collected during the entire summer, the spe- 
cies is uncommon from May until early in October when it may 
