266 DIPTERA OF NORTH AMERICA. [PART IV. 



Table for determining the species. 



/ Anterior margin of the wings shaded with brownish. 



1 < 1 inconstans 0. S. 

 \ Anterior margin of the wing not shaded with brownish. 2 



2 ( Wings spotted with brown. 3 

 I Wings not spotted with brown. 4 

 /-The inner end of the fourth posterior cell is in one line with the inner 



o I end of the fifth and of the discal cells. 5 vernalis 0. S. 



j The inner end of the fourth posterior cell is beyond the inner end of 

 *- the fifth and of the discal cells. 4 hyperborea 0. S. 



4 ( First submarginal cell shorter than the second. .2 auripennis 0. S. 

 \ First submarginal cell longer thari the second. 3 calcar 0. S. 



Description of the species. 



1. A. incoi&S tarns 0. S. £ and £ • — Ochracea, thorace rufescente, 

 abdomine obscuriori ; alarum margine antico et venulis transversis in- 

 fuscatis ; prsefurcse initium appendiculatum ; cellula submarginalis 

 prima secunda brevior. 



Ochraceous, thorax reddish, abdomen somewhat darker; anterior margin 

 of the wings and transverse veins infuscated ; the prsefurca has a stump 

 of a vein near its origin ; the first submarginal cell (in normal speci- 

 mens) is shorter than the second (Tab. II, fig. 15). Long. corp. 0.45 — 

 0.55. 



Syn. Amalopis inconstans 0. Sacken, Proc. Ac. Nat. Sc. Phil. 1859, p. 247. 



Coloring very inconstant ; ochraceous, more or less mixed with 

 brown on the thorax and the abdomen ; sometimes altogether 

 without brown. The following is the description of the speci- 

 mens with a fully developed dark coloring : — 



Ko strum and palpi brown ; front grayish ; under side of the 

 head yellowish ; antennae pale, but little longer than the head ; 

 basal joint generally brownish ; flagellum with moderate verticils. 

 Collare ochraceous, a black ring near the head, a brown stripe 

 along the middle ; mesonotum yellowish-orange, with a slight 

 brown tinge along the middle ; stripes indistinct ; back of the 

 suture, the thorax is brownish ; scutellum and metathorax are 

 paler in the middle ; pleurae pale ; halteres pale ; feet yellow, 

 femora and tibiae faintly brownish at the tip ; tips of the tarsal 

 joints, and their last joint brown. Abdomen brown, especially 

 towards the tip ; male genitals brown; ovipositor reddish. Wings 

 tinged with light brownish ; anterior margin, especially within 



