DIPTERA— HELOMYZID^. 



547 



Family HELOMYZID.^ Westwood. 



HETEROMYZA Falldn. 



Heteromyza senilis. 



PI. 3, Figs. 1, 2. 

 Heteromyza senilis Sciuld., Rep. Progr. Geol. Siirv. Can., 1875-1876, 27.5 (1877). 



In tliis case we liave but a fraijment of one win"-, but one which exhibits 

 most of the peculiarities of neuvation, and, so far as it goes, very well pre- 

 served. The wing is sliglitly discolored, but was apparently hyaline in life, 

 covered rather profusely with exceedingly delicate microscopic hairs which 

 cover veins as well as membrane ; the veins, excepting- the costal, are testa- 

 ceous ; the costal vein is blackish fuscous, covered witli short bristles, and 

 extends beyond the third longitudinal vein, where the wing is broken ; the 

 auxiliary vein strikes the costa at about the end of the first quarter, and the 

 nearly straight first longitudinal vein before the middle of the wing ; this 

 latter vein is bare or only feebly pubescent ; the slightly sinuous, toward the 

 extremity slightly upturned, second longitudinal vein divides about equally 

 the space between the costa and the third longitudinal vein ; the latter is 

 almost straight, scarcely bending to receive the small transverse vein at 

 about the end of its basal third, and terminates at the broadly rounded tip 

 of the wing; the small transverse vein lies just before the tip of the first 

 longitudinal vein; the fourth longitudinal vein is nearly straiglit, only bent 

 next the transverse veins ; before the small transverse vein it is parallel 

 and rather closely approximated to the third longitudinal vein ; beyond, it 

 diverges slightly and regularly from it, and beyond the large transverse 

 vein again becomes parallel to it; only the basal portions of the fifth and 

 sixth longitudinal veins are present, and the extreme base of tlie wing is lost; 

 but the basal cells are evidently small, and their extremities lie just beneath 

 the union of the second and third longitudinal veins; the wing is broad, 

 ovate, and well rounded ; the costa pretty strongly arched. 



Length of fragment, 4™'"; probable length of wing, 4.5"""; probable 

 breadth of same, 2°"". 



Quesuel, British Columbia. One specimen, No. 1 (Dr. Gr. M. Dawson, 

 Geological Survey of Canada). 



