SUBFAMILY CALLIPHORINAE 33a 
Biology, habits, and immature stages. Egg. Macrotype, ap- 
proximately 2.0 mm. in length and about three times as long 
as the greatest diameter; clearly white, rather glistening, longi- 
tudinally striate, feebly reticulate. 
The eggs hatch in from 24 to 48 hours during early August 
in the vicinity of Logan, Utah. 
Larva. Third instar: Length 12-22 mm., typically muscoid 
in habitus, creamy white in color. Cephalic segment (pl. 45, E) 
with well-defined, branching, oral grooves radiating from the 
oral opening. Segments 2 to 7 anteriorly with complete spinose 
bands, segments 8 to 11 bare anterodorsally, segments 2 to 5 
bare posteriorly, segments 10 and 11 posteriorly with complete 
spinose bands, segments 2 to 9 bare posterodorsally, segment 12 
with complete anterior spinose band. Spines minute, single- 
pointed, lightly pigmented. Anal protuberance large, above and 
below with extensive spinose areas. Inner tubercle on dorsal 
margin of posterior depression largest, median and outer tuber- 
cles smaller and closer together; outer tubercle on ventral margin 
of posterior depression largest, median slightly smaller, these 
two tubercles closer together than inner and median tubercles; 
each of these tubercles becomes pigmented with maturity of 
larva. Anterior spiracles large, each with 7 or 8 rounded ori- 
fices; posterior spiracles each (pl. 45, F) with three nearly 
parallel slitlike apertures, the ‘‘button’’ well-defined and 
located in peritreme, small, lightly pigmented. Cephaloskeleton 
(pl. 45, E) strongly sclerotized and deeply pigmented, labial 
selerite strongly curved, the width of the basal portion nearly 
one and one-half times the length of the entire sclerite, both 
dorsal and ventral cornua pigmented throughout, the ventral 
cornua with longitudinal ridges typical of saprophagous larvae, 
hypostomal sclerite short, the pair united ventrally. 
Larvae leave their food in three or four days and most of 
them pupate in about 9 days. A few may pupate as soon as 6 
days and others may delay pupation for as long as 15 days. 
Puparium. With most of the external characters of the ma- 
ture larva. 
Adult. The species occurs during July and August at an alti- 
tude of from 6 to 9 thousand feet in meadow areas in the 
northern portion of the Rocky Mountain ranges of the United 
States. It is one of the most difficult of all of the blowflies to 
catch in nature. The adults are not only very active, but they 
are also among the swiftest flying species of the Calliphoridae. 
They do not circle slowly in flight as do species of Calliphora or 
