SUBFAMILY CHRYSOMYINAE 189 
rounded, nearly bare and without trace of oral grooves; second 
segment flattened, with the spines arranged in rows and increas- 
ing in length toward margin. Cephaloskeleton (pl. 38, B) 
heavily sclerotized and pigmented; labial sclerites small, strongly 
eurved, nearly triangular; hypostomal sclerites slightly longer 
than hooks, broad, strong; parastomal sclerite broad, shortened; 
ventral cornua broad, short, without longitudinal rows on ven- 
tral margin; dorsal cornua long and strong. Respiratory system 
with anterior spiracles each with seven or eight apertures in fan- 
shaped arrangement; posterior spiracles (pl. 38, A) each with 
three well-defined, nearly parallel apertures, the innermost aper- 
ture set slightly apart from other two, ‘‘button’’ nearly trans- 
parent but still distinct, peritreme nearly indistinct ventrally 
but well defined dorsally, ovate below but nearly round above. 
Anal segment subtruneate, the spiracles in a shallow cup-shaped 
mid-dorsal cavity which is margined by six low bare anal pro- 
tuberances, these distinctly marked by encircling rows of minute 
spines. 
Pupa. With most of the external characters of the mature 
larva; 7-10 mm. in length and 3.5-4 mm. in diameter; of typical 
ealliphorid habitus. 
According to Dobrosecky (1925), the larva of avium was 
described and illustrated under the name Protocalliphora azurea 
(Fallen) by Coutant (1915), who collected larvae from nests 
of Corvus brachyrhynchos brachyrhynchos Brehm (Eastern 
Crow), at Ithaca, N. Y. Coutant states that these larvae were in- 
termittent feeders on the blood of this host and that such larvae 
may be found crawling about through the feathers of nestling 
birds. He was not able to rear such larvae to maturity by feed- 
ing them upon solid flesh, either fresh or decayed. 
Jellison and Philip (19338) stated that every occupied nest of 
magpie and crow examined by them in the Bitterroot Valley, 
southwestern Montana, contained aviwm larvae, as many as 373 
larvae being taken from a single magpie nest. These larvae were 
confined to the fibrous mass of rootlets and stems which line such 
nests and to the accumulation of very dry scaly duff that had 
sifted through this mass to the tight mud-plastered floor. The 
larvae were not found on or near the fledglings, but bright red 
blotches of undigested blood showed plainly in the foregut. 
Larvae were dissected and stained smears of gut contents showed 
nucleated erythrocytes of avian blood. The pupal period of 983 
reared specimens was found to average 11.02 days at room tem- 
perature (approximately 24° C.) during May and June. Jellison 
and Philip said ‘‘The nests of magpies and crows appear to offer 
