SUBFAMILY POLLENIINAE 359 
Melanodexiopsis pacifica, new species 
A species with the general aspect of tristina, but which has the 
middle tibia with ventral bristles and only one postacrostichal 
bristle. 
Male. UHead with epistoma long, slightly narrower than 
elypeus, and then widening below vibrissae which are high above 
the oral margin. 
Thorax with one postacrostichal bristle. 
Legs with middle tibia with two strong and one weak ventral 
bristles, two strong anterodorsal bristles, and three strong pos- 
terior bristles; hind tibia with two anteroventral bristles. 
Female. Unknown. 
Type. Male, No. 54940, U. S. National Museum. 
Length. 9 mm. 
Type locality. Pacifie Grove, Calif. 
One female (June 8, 1917, T. E. Snyder). 
Melanodexiopsis tristina, new species 
Melanodexia tristis Shannon (nee Williston), Wash. Ent. Soe. 
Proce. 28(6) :187, 1926. 
This species wag considered to be the same as Melanodexia 
tristis Williston by Shannon, but Williston’s type, a male at 
Kansas University, is glabricula Bigot according to Aldrich. 
A glabrous black species with hyaline wings and with the 
middle and hind tibia without ventral bristles. | 
Male. Head width and height 11.5, length at antenna 7.3 and 
at vibrissa 6.8; eye height 8.5; bucca 0.39 eye height, shining 
black or with thin silvery pollen, and with scattered black hairs, 
none of the hairs pale; frontale very narrow near ocelli, rapidly 
widening anteriorly to slightly above lunule where it becomes 
narrower again, anteriorly reddish orange, posteriorly black; 
front at narrowest 0.7 of head width, 0.17 at vertex and 0.5 at 
lunule, with thin silvery pollen, and with scattered black hair 
which becomes most abundant anteriorly and extends to facial 
groove below; frontal row consisting of nearly 14 bristles, the 
rows extending to base of third antennal segment anteriorly, 
the bristles long and strong toward lunule, weaker posteriorly, 
and weak or hairlike just anterior to foremost ocellus; vertex 
subpollinose, black; ocellar triangle with long, black, erect or 
proclinate hair; parafaciale narrowed above, about 2.4 in width 
opposite lunule, black, with silvery pollen; vibrissae strong, above 
oral margin by 1.2 and separated by 2.0; palpus 3.0 in length, 
