286 THE BLOWFLIES OF NortH AMERICA 
mens show well-developed accessory ocellar bristles and from 
four to six lateral scutellar bristles. The smallest specimens of 
this species often have weak accessory ocellar bristles and but 
three lateral scutellar bristles. 
Distribution. Nearectic: Highlands of northern Mexico to 
British Columbia and east to Ontario, Canada; most abundant 
in the Rocky Mountain states north of Colorado. Numerous 
specimens which I collected at high elevations during June, 
1945 on the island of Oahu, Hawaiian Islands, are doubtfully 
placed under this name. Although the species may occur as 
early as February at Tempe, Ariz., it is most abundant during 
June and July from Colorado northward. 
The type series of Calliphora latifrons Hough has been dis- 
tributed among a considerable number of collections. Several 
(from Moscow, Idaho) were in the Aldrich collection, now in 
the National Museum; a Seattle, Wash., specimen is also evi- 
dently part of this series and is in the same collection. Several 
specimens in the Hough Collection in the Field Museum at 
Chicago, Ill., are evidently part of the type series. They com- 
prise three specimens from Seattle, Wash., four from Moscow 
Mountain, Idaho, and one from Pullman, Wash. Hough did not 
indicate his holotype; I have selected a male from Moscow, 
Idaho, in the Field Museum as the lectotype. 
Biology, habits and immature stages. Egg. Approximately 
1.8 mm. in length and 0.4 in greatest diameter, white, striate, 
and slightly reticulate. 
The eggs are deposited in small clusters of from 6 to 8 eggs 
each. They hatch in 24 to 48 hours during late July and early 
August in the vicinity of Logan, Utah. 
_ Larva. Second instar: Segments 2 to 8 anteriorly with com- 
plete spinose bands, segment 9 bare dorsally, segments 10 and 
11 with complete posterior spinose bands, segment 12 bare dor- 
sally; segments 7 to 11 ventrally with both anterior and posterior 
spinose bands. Inner and outer tubercles on dorsal margin of 
posterior depression large and of about equal size, the inner 
tubercle smaller and set closest to outer; the outer tubercle on 
ventral margin of posterior depression largest, the median tuber- 
ele but slightly smaller, these two set closest together. Anterior 
spiracles each with 8 (sometimes 7 or 9) rounded orifices; pos- 
terior spiracles (pl. 42; C) each with two well-defined, more or 
less slit-like apertures, the outer one of which is bent outward 
toward the middle, the ‘‘button’’ indistinct and peritreme 
lightly pigmented toward the ‘‘button’’ area. Cephaloskeleton 
(pl. 42, A) well sclerotized, the labial sclerite broad basally as 
