170 NEW NORTH AMERICAN ANTfTOMYIIDAE (dIPTERa) 



Natural Sciences of Pliiladelpliia and the Illinois Natural History 



Hui'vey. 



Hydrophoria polita sp. ii. 



Male. — This species most closely resembles arctica Malloch, but the basal 

 hypopygial segment, on the greater portion of its surface above, is armed 

 with weak erect hairs, the stout bristles bebig confined to apical half. The 

 eyes are separated at narrowest part of frons by a distance about as wide 

 as anterior ocellus; the longest hairs on aiista are as long as width of third 

 antennal joint; the hind femur has strong bristles from base to beyond middle 

 on postero-ventral surface. 



Female. — Similar in general api)earance to the female of divisa. The 

 abdomen is much less noticeably shining than in arclica, without distinct 

 lateral checkerings, and the dorso-central vitta does not reach apex. Chae- 

 totaxy of legs as in mal(\ 



Length, 7 to 7. .5 mm. 



Type. — (f ; Bozeman, Montana, elevation 5400 feet, July 23, 

 1902, [Mont. Aoric. Station]. Allotype. — 9 ; topotypieal. Paid- 

 type. — cf ; in pool' condition, Wells. Nevada, July 12, 1911, 

 (Aldrich). 



Hydrophoria katmaiensis sp. n. 



Male. — Differs from llie general rule in the genus in haA'ing the tibiae largely 

 rufous-yellow, and the long hairs at junction of caly])tra brown or fuscous. 



Eyes se|)arated by about width of anterior ocellus; parafacial much nar- 

 rower than in polita, not as wide as third antennal joint; cheek very much 

 rounded off posteriorly. Basal hypopygial segment with rather long bristly 

 hairs; armatureof dorsum of abdomen weak, in sharp contrast to the strong 

 bristles on the portions of doisal segments which curve under abdomen, 

 especially to those on incurved poitions of segments three and four; fifth 

 sternite with long bristl>- haii's, tlu> ])rocesses fringed on basal half of their 

 inner margins. Hind fenuu- with Ijristles to beyond middle on postero- 

 ventral surface; hind tibia with two long and one or two short (basal) bristl(>s 

 on postero-dorsal surface. Costal thorn very small. Length, 6.75 mm. 



Type.—d"; Katniai. Alaska, August, 1917, (J. S. Hine), [Coll. 

 Hine]. 



Hydrophoria occidentalis s]). n. 



Male. — Similar to polita in general ai)i)carance, but the hypoingiuni has 

 only slender hairs on basal ]>ortion, the preceding segment is largely pruine- 

 scent and armed with numerous hairs, and the hind tibia has but three 

 postero-dor.sal bristles. Length, 7 nun, 



Type.—d^; Wells, Nevada, July 12, 1911. Pamlypc.—d^; 

 Piilliiiaii, Washington, Juiu' S, 1898, [Wash. Sla. Coll.|. Type 

 in riiilccl ion (if Di-. Ahhich. 



