298 THE BLOWFLIES oF NortH AMERICA 
tened, black, silvery pollinose, with three or four rows of post- 
ocular cilia and some yellowish hair about occiput; metacephalon 
black with mostly black hair. 
Thorax with color and chaetotaxy mainly like vicina but with 
three postintraalar bristles; hindmost preacrostichal, dorsocen- 
tral and preintraalar bristles 2.8, 1.6 and 1.0, respectively, before 
the suture; sclerites at wing-base black; spiracles with dark 
tawny brown hair. 
Legs with bristles as in vonitoria but middle tibia with two 
anterodorsal bristles, two posterior bristles and one posterodorsal 
bristle; hind tibia with three or four anterodorsal bristles, two 
or three posterodorsal bristles. 
Wing brownish at base; basicosta black;. subcostal selerite 
orange brown with orange pubescence; costal sections 2 to 6 in 
the proportion 83 :54:104:40:8; squamal lobes similar to those 
of vicina. 
Genitalia with forceps (pl. 27, H and I) as illustrated. 
Female. Head height 14.7; length at antenna 6.8 and at vi- 
brissa 7.8; eye height 7.2; bueca 0.44 eye height; parafaciale 1.9 
in width opposite lunule; vibrissae set 3.6 apart; front at nar- 
rowest (at vertex) 0.34 of head width, 0.40 at lunule; frontale 
wide, usually velvety black but sometimes rather brownish 
toward lunule. Wing with costal sections 2 to 6 in the proportion 
90 :60 :142 :50:6. Otherwise similar to NS except for normal 
sexual differences. 
Length. 7-11 mm. 
Type. Male, No. 54934, U. S. National Museum. 
Type locality. Savannah, Ga. 
. Kastern males sometimes have the front at the narrowest 
slightly narrower than 0.05 head width; the width at the lunule 
-especially may be reduced. 
Walton (1913) investigated variation in the chaetotaxy in a 
series of 247 specimens of this species which had been reared 
from a dead snake. He stated ‘‘In nearly all cases where super- 
-numerary intraalar bristles occurred they were smaller than 
normal. In other words there was an apparent tendency of the 
‘most cephalad toward obsolescence. In several cases no less than | 
five macrochaetae replaced the usual three, the more frequent 
‘number, however, was four and the aberration was bisym- 
metrical or otherwise. Two individuals possessed but a single 
pair of posterior intraalars on each side and could therefore not 
be distinguished structurally from Calliphora vicina.’’ 
Distribution, Nearctic: California and Georgia to as far 
