SUBFAMILY MESEMBRINELLINAE 81 
striking, black, converging hair-tufts which touch on the median 
line. Internal features as illustrated (pl. 12, E and F). 
Female. Unknown. 
Length. 8.3 mm. 
Huascaromusca tibialis (Aldrich), new combination 
Mesembrinella tibialis Aldrich, U. S. Natl. Mus. Proce. 62(11) :16, 
1922. (Type, male from Porto Bello, Panama, No. 25247, 
U.S. National Museum.) 
An orange-brown species with the dorsum of the thorax brown, 
dorsum of abdomen except at base metallic blue, and the tibiae 
and tarsi dark brown. 
Male. Head height 12.4; width 15.4; eye height 11.0; length 
at antenna 7.0, and at vibrissa 6.0; bucca 0.12 of eye height, deep 
orange, mostly shining, and with both black and orange hair; 
frontale orange brown; parafrontale orange; eyes contiguous for 
a short distance; front at vertex 0.10 of head width, 0.18 at 
lunule; frontal row of bristles not continuing posteriorly beyond 
the narrowest portion of front and composed of about five 
bristles, only the anterior ones strong; a few weak dark hairs on 
parafrontale outside frontal row; parafaciale 0.8 in width 
opposite lunule, narrower below; faciale low, rounded, with a 
few black hairs above the vibrissa; vertex brown, brown pol- 
linose; ocellar triangle with weak postocellar bristles behind 
posterior ocelli; vibrissae slightly above oral margin and set 4.0 
apart; antenna deep orange, third segment 2.5 times as long 
as second; palpus orange, 4.0 in length; metacephalon orange; 
back of head black, grayish yellow pollinose, with one row of 
postocular cilia and tawny hair. 
Thorax deep orange, dorsum orange brown with brown pollen, 
with a shining middorsal stripe and a lateral stripe outside the 
dorsocentral row of bristles, neither of which extends to the 
seutellar suture; fine thoracic hair mostly black; humerus orange, 
with two bristles, and with fine black hair; sternopleural bristles 
two; preacrostichal bristle one, this placed 2.7 before the suture; 
hindmost predorsocentral bristle placed 1.6 before the suture; 
postacrostichal bristle one; sclerites at wing base orange to 
orange brown; lesser ampulla dark brown; propleural bristle 
one; mesospiracular bristle one; spiracles with orange hair, the 
metathoracie spiracle with fine long black hairs on the ventral 
margin; scutellum deep brown, rather metallic purple in certain 
lights, under surface with dark hair, lateral bristles two; post- 
scutellar plates with black setae. 
Legs with coxae, femora and pulvilli orange, the femora 
