272 THE BLOWFLIES oF NortH AMERICA 
clavate; third segment of antenna usually three, but sometimes 
four or more, times as long as second and reaching nearly to 
vibrissal level; arista with penultimate segment short, not 
bulbous, and with long plumosity above and below; back of head 
usually but slightly rounded or flattened, not protuberant. 
Thorax with propleuron strongly setose; prosternum setose, of 
moderate size, narrowing posteriorly; tympanic pit setose on 
outer rim or more; sternopleural bristles three, arranged 2:1; 
parasquamal tuft absent; squamal process setose; lateral post- 
scutellar plates strongly setose; scutellum with three to six lateral 
bristles, the under surface bare in center. 
Wing with lower squamal lobe pilose above. 
ACRONESIA, NEW GENUS 
Steringomyia Shannon (nee Pokorny), Insecutor Inscitiae Men- 
struus 11:107, 111, 1928; Wash. Ent. Soc. Proc. 28(6) :134, 
1926. 
Male and female. Head (pl. 6, A) width about one-sixth 
greater than height; length at antenna and at vibrissa approxi- 
mately equal; epistoma elongate, strongly warped forward from 
elypeal plane, and nearly as wide as clypeus; clypeus moderately 
depressed, wide, rather cup-like; eye small or of but medium 
size; frontal bristles extending anteriorly to lunule only; anterior 
portion of frontale usually obscuring lunule; inner vertical 
bristles strong, decussate, outer vertical bristles absent in male 
and about two-thirds as long as inner in female; frontoorbital 
bristles absent in male, two proclinate and one reclinate in fe- 
male; ocellar bristles erect or proclinate; facial carina not ap- 
parent but often low and rather broad, not separating antennal 
bases; parafaciale of nearly equal width above and below, and 
with minute scattered black setae on upper third or more; faciale 
curved more or less anteriorly below toward vibrissal angle, and 
with stout black setae which ascend toward the antennal bases; 
vibrissae strong, slightly above the oral margin; proboscis nearly 
equal in length to head height; palpus narrow-clavate; antennal 
base at eye middle when head is viewed in profile, the bases ap- 
proximated, third segment three times as long as second, reaching 
at least three-fourths the distance to the vibrissa; arista with 
penultimate segment about one and one-half times as long as 
the diameter, apical segment elongate, uniformly tapering to 
apex, with short to medium-length cilia for 0.60 its length; back 
of head slightly rounded, rather bulging below. 
Thorax blackish, with four humeral bristles; propleural bristles 
