SUBFAMILY CHRYSOMYINAE 
The ‘‘serewworm”’ species, the “‘black blowflies’’ of authors, 
and the ‘‘nestling screwworms’’ of this country belong to this 
subfamily. Buiologies, habits, and immature stages of only a 
few of the species are known. 
All the species belonging to the Chrysomyinae have the remi- 
cium ciliate posteriorly at the base. The subfamily may be di- 
vided into two tribes upon superficial examination. The species 
of Chrysomyini have blue or green metallic bodies, bright orange 
heads, reddish or black legs, and most of them have dark longi- 
tudinal stripes on the dorsum of the thorax. The species of 
Phormiini are dull olivaceous-green or bluish-green species with 
black heads and legs. 
Flies of the tribe Chrysomyini are the abundant blowflies of 
the tropics of North and South America. None of the species of 
the tribe Phormiini apparently occur much farther south than 
Mexico City. Almost every rotting animal and vegetable sub- 
stance in any locality has its fauna of one or more of the various 
species which belong to the tribe Chrysomyini. Not even the 
abundant housefly, Musca domestica L., is more numerous in the 
market places in the American Tropics, and only in the immediate 
vicinity of stables and corrals are blowflies outnumbered by any 
other flies. 
The North American representatives of Chrysomyinae have 
the following characters in common. 
Male and female. Head width greater than height; front nar- 
rower in male than in female; inner vertical bristles present; 
postvertical bristles weak, reclinate frontoorbital bristles usually, 
and proclinate frontoorbital bristles usually absent in male, but 
one or two proclinate and one reclinate frontoorbital bristles 
usually present in female; ocellar bristles proclinate in male, pro- 
clinate to divaricate in female; facial carina absent or very 
slightly developed; proboscis two-thirds to three-fourths head 
height; haustellum one-third to one-half head height, setose; 
labellum of moderate size; antennal base at or but slightly below 
middle of eye in profile, the bases either approximated or but 
slightly separated; arista with the terminal segment elongate, 
slightly thickened at base, and gradually tapering to apex, 
plumose above and below two-thirds to four-fifths the distance 
from base to apex. 
Thorax with propleuron strongly pilose; propleural bristle 
strong; notopleural bristles usually two; pteropleuron bare on 
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