Diptera 53 c 



Length, 2 mm. 



Type Locality: Nome, Alaska, August 21, 24, and 25, 1916 (F. Johansen). 



This species runs down to perplexa Malloch in the paper previously referred 

 to, but the colour of the legs, and the weaker tibial setulse are sufficient to warrant 

 their separation. 



Aphiochaeta, sp. 



A female in poor condition appears to be distinct from the previous species. 

 It has the hind tibial characteristics of that species as well as the l>:u<> meso- 

 pleura, but in venation it agrees more nearly with alaskensis. It is not possible 

 to satisfactorily describe the species. 



Locality: Nome, Alaska, August 24, 25, 1916 (F. Johansen). 



BORBORID^E. 



The larvae of this family live in manure, fungi, decaying vegetation, or, 

 rarely, in putrid water in which there is decaying animal or vegetable matter. 



Several species are commonly found in marshy spots, and I have seen the 

 imagines running upon the surface of stagnant water. In winter and early spring 

 some species occur under dry grasses amongst dead leaves, and when disturbed 

 jump violently about much as do springtails found in similar situations. 



There is only one species of the family in the collection. 



Leptocera Olivier. 



The species in this collection seems to be undescribed. 

 Leptocera transversalis, n. sp. 



FEMALE (alcoholic specimen). Head yellow, ocellar triangle, upper half 

 of occiput, greater portion of third antennal joint, arista, and clypeus black. 

 Thorax black, lateral margins, centre of scutellum, and the pleural sutures 

 broadly, yellowish. Abdomen brownish black dorsally, venter largely yellow. 

 Legs black, trochanters, apices of femora, bases of tibise, and the tarsi yellowish. 

 Halteres pale. Wings clear. 



Ocellar triangle large, sharp anteriorly, extending over midway from 

 vertex to anterior margin of frons; orbital bristles three to four on each side, 

 short but strong; interfrontalia with short setulose hairs, antennae rather large, 

 third joint rounded apically; arista very much shorter than in typical Leptocera, 

 not twice as long as antenna, thickened at base, distinctly tapered, microscopi- 

 cally pubescent; vibrissa weak, genal bristle absent, the marginal bristles very 

 short; cheek about one-third as high as eye. Thorax with numerous discal 

 setulose hairs and only one distinct pair of bristles in dorso-central series, just 

 in front of scutellum; posthumeral bristles absent; scutellum rounded, with a 

 few very short discal hairs and four moderately long marginal bristles. Legs 

 slender, without any distinct bristles, even on femora; hind tarsi with basal 

 joint twice as long as second. Wing venation as in PL VIII, fig. 20, differing from 

 that of most species of this genus in having the cross-veins very nearly directly 

 below apex of first vein. 



Length, 2-5 mm. 



Type Locality: Pond at Collinson point, Alaska, June 13, 1914 (F. Johansen) . 

 Two specimens. 



This species differs so strikingly from others in Leptocera that it might be 

 placed in a new genus, but as several workers are now engaged in revising the 

 family I prefer to leave its removal from or retention in the genus to their decision. 



The larvae of the species in the present collection are either aphidophagous 

 (Syrphus, etc.) or feed in sewage or decaying vegetable matter such as is found in 

 s,wampy places (Helophilus). 



