82 c Canadian Arctic Expedition, 1913-18 
HELOMYZIDyE. 
The larvse of this family live in carrion and manure. Some of the species 
are found in caves and in underground nests of rodents. 
The family is represented in this collection by imagines only. In order to 
facilitate the indentification of the genera in this paper a generic synopsis is 
given herewith. 
Key to Genera. 
1 . Humeral bristle present 2 
Humeral bristle absent 3 
2. Thorax with five dorso-centrals Helomyza Loew. 
Thorax with two dorso-centrals Achaetornus Coquillett. 
3. Thorax with one pan- of dorso-centrals Porsenus Darhngton. 
Thorax with at least two pairs of dorso-centrals 4 
4. Mid tibiae with long bristles on middle Oecothea Haliday . 
Mid tibiae without bristles except at apex. 5 
5. Thorax with five or more pairs of dorso-centrals : 6 
Thorax with two pairs of dorso-centrals Neoleria, gen. n. 
Thorax with three pairs of dorso-centrals Tephrochlamys Loew. 
Thorax with four pairs of dorso-centrals 8 
6. Scutellum with six bristles; inner cross-vem much before end of first vein; mesopleura 
bare Anorostomoides Malloch. 
Scutellum with four bristles 7 
7. Inner cross-vein distinctly before end of first vein; frons in male very narrow; propleural 
and mesopleural bristles present Heteromyza Fallen . 
Inner cross-vein at or beyond end of first vein; propleural and mesopleural bristles 
absent; eyes of male widely separated AUophyla Loew. 
8. Eyes very small, not much larger than antennae; arista remarkably long; vibrissae 
strong Eccoptomera Loew . 
Eyes much larger than antennae; arista short; vibrissae short and weak; face receding, 
oral margin not developed Anorostoma Loew. 
Eyes large; arista long; vibrissae strong; mouth margin weU developed Leria Loew. 
Oecothea Haliday. 
There is a large series of a species of this genus in the collection. I cannot 
identify it with any of the previously described European species and it differs 
essentially from fenestralis Fallen— a species occurring in Europe and North 
America. 
Oecothea aristata, n. sp. 
Male AND Female.— Head, anterior lateral angles of thorax, greater portion 
of scutellum, hypopygium of male, genital segments of female, and the legs 
reddish testaceous; upper portion of head and greater portion of occiput, thorax 
abdomen, coxae, sometimes median portion of femora, and whole of tarsi fuscous. 
Wings yellowish, cross-veins not infuscated. 
Frons about two-thirds the width of head, orbits with one bristle near 
middle; interfrontalia with sparse, short hairs; antennae small, third joint barely 
longer than second; arista very slender, nearly bare, about 2-5 as long as head, 
with a very short swelling at base; face with a broad central carina which is 
flattened and broadened below, covering the entire centre of face, cheeks with 
one strong vibrissa and a number of short setulse; eye about equal in height 
to cheek at posterior margin. Three pairs of postsuturals present; propleura 
with one bristle; a few short setulae below anterior spiracle; mesopleura with 
or without a short bristle; sternopleura with one long bristle and a number of 
short setulse; pteropleura bare; hypopleura with a number of minute setulse 
below spiracle; scutellum bare on disc, margin with four bristles. Abdomen 
of male subcyb'ndrcal, fifth sternite with short, stubby setulae on apical half; 
hypopygium large, knob-like; al)domen of female more flattened, genital 
segments small. All femora of male slightly thickened, their antero- and postero- 
ventral surfaces each with a series of short black bristles; femora of female not 
