Diptera 55 c 



Syrphus sodalis, var., interruptus var. n. 



A female taken west of Kongenevik, Camden bay, Alaska, July 4, 1914, 

 differs from the other specimens in having the abdominal yellow marks much 

 smaller, the basal segment having two short, spot-like marks which do not reach 

 the lateral margins, and the other segments having narrow, almost linear, marks. 

 The antennae are entirely black, and the tibise yellow. In other respects coloured 

 as type form. 



Length, 8 mm. 



Helophilus Meigen. 



The larvae of species of this genus are as far as known found in mud and 

 decaying vegetable matter in or along the margins of ponds or streams. 



Helophilus dychei Williston. 

 Helophilus dychei Williston, Can. Ent., vol. 29, p. 135, 1897. 



Two specimens of this species are in the collection from Nome, Alaska, 

 August 24 and 25, 1916, and in that from Bernard harbour. Northwest Territories, 

 on Dryas flower, July 6, 1916 (F. Johansen). 



The species has previously been recorded from Alaska, being originally 

 described from Sitka. 



OESTRIDy^. 



Only three imagines of this family are in the present collection, but there 

 are a number of larvae of two species. 



(Edemagena tarandi (Linne.) 

 Oestrus tarandi Linne. Faune Suecia, p. 1731, 1761. 



Female. — Three females of this species were taken. 



The species superficially resembles Hypoderma lineata De Vill., but the 

 distinct palpi, and larger size, 15 mm, in addition to the differently coloured 

 abdominal hairs readily separate it from that species. A brief description of 

 the species is given as few descriptions in English are available to students.^ 



Head black, apex of second antennal joint and arista brown; hairs on frons, 

 parafacial, and the upper half of face black, on occiput except along margin 

 of eyes, on cheeks, and lower half of face pale yellow; palpi and, proboscis black. 

 Thora:ic dorsum with long, erect, pale yellow hairs in front of suture and on 

 postalar callosity, with black hairs caudad of suture; disc opaque black, with 

 two submedian linear vittae in front of suture which are evident behind suture 

 as two small spots, and with two broad lateral vittae behind suture which are 

 present in front of suture as two small spots; pleura and scutellum with long 

 pale yellow hairs. Abdomen with long pale yellow hairs on first segment, 

 and similar hairs of a bright reddish orange colour on segments 2, 3, and 4 

 both on dorsum and venter. Legs black, tibiae except bases, and the tarsi 

 tawny; all parts with black and yellow hairs intermixed, the pale hairs longer 

 and more conspicuous at bases of femora and on apical halves of tibaie. 

 Posterior basal cross-vein of wing distad of anterior; fourth vein continuing 

 parallel to third for a considerable distance beyond outer cross-vein before 

 curving forward. 



Localities: Teller, Alaska, July 31, 1913; one specimen; Bernard Harbour, 

 Northwest Territories, July 14, 1916, two specimens (F. Johansen). 



LarVjE. — I identify as of this species larvae taken from under the skin of 

 Barren Ground caribou. The species was originally described from northern 

 Europe and has been recorded from Alaska. The recorded host is the reindeer, but 



' For an account of (Edemagena tarandi see G. H. Carpenter, Tonon. Econ. Biol., vol. 5, pp. 149-156, 1910. 



