Diptem 51 c 
Male and Female. — Black, with a distinct greenish lustre. Frons opaque 
black-brown; antennae black; face greenish above, the surface with dense brown- 
ish pollen which rarely obscures the entire surface in either sex^ face, below, 
entirely silvery pilose in the male, but in the female the greater portion is brownish 
pilose with normally a whitish area on each side; postocular region with numerous 
black bristles and yellow hairs. Thorax almost black, with a cupreous stripe- 
along line of dorso-centrals and a broad sublateral vitta each side. Abdomen 
with a more pronounced greenish tinge than thorax and usually slightly cupreous 
on dorsum at base. Legs black, distinctly green-tinged, especially on dorsal 
surfaces of tibiae. Wings clear, with a distinct brown spot on cross-vein and 
another before middle of last section of fourth vein. Squamae with pale fringes. 
Male. — Third antennal joint short, obtuse at apex; face in both sexes 
broad, slightly widened below, the upper half slightly vertically rugose. Pro- 
pleura with a group of bristly black hairs above coxa, among which the normal 
bristle is barely distinguishable. Scutellum with four strong bristles. Fore 
femora in male excavated at apex below, and with four to five short stout bristles 
basad of the excavation, on the anterior side; base of femur slightly swollen, 
and near its antero-ventral edge with a series of five to seven widely-placed 
setulae; ventral surface of fore tibia with a series of closely placed spines; fore 
tarsi normal; mid and hind femora not swollen, both pairs with a few bristles 
on apical half of antero- and postero-ventral surfaces; mid and hind tibiae 
with a few widely placed bristles. 
Female. — Similar to male except that the fore femora are not excavated 
near apex and lack the group of bristles on the antero-ventral side, and the 
fore tibia has less regular and slightly longer ventral bristles. 
Locality: Teller, Alaska, two specimens, July 29, 1913, and ten specimens, 
August 6, 1913 (F. Johansen). 
Originally described from Commander islands, Bering sea. 
Hydrophorus pilitarsis, n. sp. 
Male and Female. — Similar in colour to the preceding species, differing 
only in having the postocular cilia on lower half almost entirely yellow, and the 
fore coxae with long yellow hairs and only a pair of black bristles at middle and 
a few black setulae at apex instead of being almost entirely black setulose. 
Male. — Face widest below middle, slightly narrowed at lowest extremity; 
antennae as in signi^erus. Propleura with one black bristle and a nimiber of 
long yellow hairs. Fore femora more noticeably swollen than those of signifenis, 
not excavated at apex near base, with seven to eight stout, closely placed, 
rather short bristles on the ventral surface; a number of long black hairs on 
apical half of posterior surface; fore tibia thickened on apical half, the antero- 
ventral surface with dense microscopic pile and very minute spinules; fore tarsi 
with long black hairs on antero-ventral margin of basal and dorsal surface of 
next three joints; mid femora with four to five long, black bristles at base on 
antero-ventral surface and moderately long, black hairs on apical two-thirds of 
postero-ventral surface, the femora slightly bent; hind femora slender, straight, 
with short setulose hairs; mid and hind tibiae with a few short bristles. Last 
sections of veins three and four conspicuously convergent apically, the dark 
spot on last section of four nearer middle of that section than it is in signiferus. 
Female. — Similar to male except that the fore femora are less thickened, 
lack the basal series of strong bristles, and have the apical series of hairs on 
postero-ventral surface less closely placed. The mid femora have two to three 
strong bristles near base. The fore tarsi have only the normal hairs. 
-Length, 3 -5-4 -5 mm. 
Type localitv: Teller, Alaska, five specimens, Julv 29, 1913; one specimen. 
August 6, 1913 (F. Johansen). 
Vol. iii— 46963— 4i 
