274 THE BLOWFLIES OF NortH AMERICA 
Acronesia abina, new species 
Steringomyia alpina Shannon (nee Zetterstedt) (in part), In- 
secutor Inscitiae Menstruus 11:111, 1923. 
Male. Head height 10.6; width 12.3; eye height 6.6; bueca 0.51 
eye height, black, with thin gray pollen and with only black 
hair; frontale brownish black, 0.40 frontal width at narrowest, 
widening anteriorly; front at narrowest 0.18 head width, 0.30 
at vertex and at lunule, black, with bright silvery or sometimes 
slightly yellow-tinged pollen, and with a few scattered black 
hairs outside frontal row of bristles; frontal bristles eight or 
nine, rather weak, all of about equal length; inner vertical 
bristles strong and decussate, outer vertical bristles a little longer 
than adjacent cilia; parafaciale 2.0 in width opposite lunule, 
orange in ground color on lower half or more, with thin silvery 
pollen, upper third with small scattered black setae; faciale 
orange, with two rows of short black setae which ascend about 
half the distance from the vibrissa to the antennal base; clypeus 
reddish brown, epistoma orange brown; vibrissae set 1.0 above 
oral margin and 3.0 apart; palpus orange, 5.0 in length; antenna 
with basal segments orange, third segment dark orange brown, 
3.5 times as long as second; arista black, with medium-length 
cilia for slightly more than half its length; back of head rounded, 
rather bulging, black, with silvery pollen, with five or six rows 
of postocular cilia, a few pale hairs below on the metacephalon. 
Thorax black, with thin whitish pollen, this apparent mainly 
on anterior of dorsum, with three to five indistinct, shining black 
stripes evident from posterior view, one between acrostichal 
rows, and one laterad of each dorsocentral row; preintraalar 
bristle one, the posterior one absent; hindmost preacrostichal 
and dorsocentral bristles before suture 2.6 and 2.2, respectively; 
seutellum laterally below with fine dark brown hairs. 
Legs with fore tibia having two posterior. bristles, one near 
middle and one near apical third; middle tibia with three antero- 
dorsal bristles, two posterior bristles and one posterodorsal 
bristle; hind tibia with two anteroventral bristles near apical 
third, four anterodorsal bristles and four posterodorsal bristles. 
Wing hyaline, slightly brownish toward base and anteriorly; 
costal sections 2 to 6 in-the proportion 87:35: 70:45:10; no spur 
at bend of fourth vein; squamal lobes white, inner portion of 
rims brownish. 
Abdomen blue black with purple and olivaceous reflections, 
with thin whitish pollen particularly on second segment and 
laterally; second, third, and fourth segments each with a mar- 
