Diptera 57 c 



penultimate ventral segment in the arctic species has more numerous anterior 

 spines than has pratti, and there are several spines along the latero-ventral 

 margin which I do not find in the latter. The apical spines are much more 

 numerous in the arctic species than in pratti. 



TACHINIDif;. 



The larvae of nearly all of the species of this family are internal parasites 

 in other insects, mostly in the larvae or pupae. 

 There are only two species in the collection. 



Euphorocera gelida Coquillett. 



Euphorocera gelida Coquillett, Revision of the Tachinidae. Tech. Ser., No. 7, U. S. Dept. 

 Agr., Bur. Ent., p. 101, 1897. 



There are thirteen specimens of this species in the collection. 



Four of the specimens differ from the others, and from the original descrip- 

 tion, in having only three pairs of postural dorso-centrals. In other respects 

 the specimens of both lots agree perfectly. 



Pinned with several of the imagines is the empty puparium from which the 

 insect emerged. A comparison of these puparia with those of Euphorocera 

 claripennis Macquart shows that the two species are not congeneric. The 

 characters of the puparium of gelida are as follows: — - 



Brownish red, subopaque; posterior spiracles black-margined, glossly. 



Surface microscopically, transversely striated; incisions between segments 

 defined by a single series of short stitch-like impressions; each abdominal 

 segment with three small depressed areas on centre of side, in each of which 

 there is an irregular line of minute elevations visible only under a high-power 

 lens; no respiratory elevations at base of abdomen; anal opening minute, consider- 

 ably proximad of apex of abdomen, surrounded by a poorly defined granulose 

 area; spiracles large, slightly elevated, especially above, general appearance and 

 slits as in PL VIII, fig. 15. 



Length, 8-9 • 5 mm. ; width, 3-3 ■ 75 mm. 



The puparium of claripennis differs in having the posterior spiracles with 

 openings very pronouncedly sinuous, almost W-shaped as in Musbidse, the 

 segments with distinct though miscroscopic locomotor spinules, and the respira- 

 tory organs at base of abdomen in the form of stalks. 



Locality: The specimens of gelida are from Camden bay, and Demarcation 

 point, Alaska, June and July, 1914 (F. Johansen): 



The puparia were from inside of the cocoons of a lepidopteron, Dasychirus 

 sp. (?) , sometimes as many as six in one cocoon. The records show that the larvte 

 of the host do not succeed in pupating. (Rearing 10). 



Peleteria Robineau-Desvoidy. 

 This genus is represented in the collection by a single female. 



Peleteria arctica, n. sp. 



Female. — Black, shining. Head black, cheeks except near posterior margin, 

 face and its sides reddish yellow, densely white pruinose; interfrontaha reddish; 

 orbits black, shining, but obscured by grey pruinescence; antennae and arista 

 black; proboscis black, palpi ferruginous. 



Thorax slightly grey pruinose, not distinctly vittate; scutellum reddish 

 yellow. Abdomen black, slightly grey prujnesce.nt on bases of segments; sides of 

 second and third segments broadly reddish. Legs black, hind tibiae reddish'. 

 Wings slightly greyish. Calyptrae white. Halteres dark brown. 



