DICRANOMYIA. U' 



vein, the latter being often indistinct ; the submarginal cell is 

 about one-third longer than the prasfurca (this relation is, how- 

 ever, variable in different specimens) ; the seventh longitudinal 

 vein is faintly sinuated about the middle ; the position of the 

 great cross-vein, as well as the inclination of the vein which 

 closes the discal cell on the inside, are variable. 



Hab. Environs of New York, on the salt-marshes, common. 

 Fort Resolution, H. B. T. (Kennicott). 



D. hderetica may be easily distinguished from D. liberta by the 

 coloring of the thorax, the shortness of the valves of the ovipositor, 

 the greater distance between the tip of the auxiliary vein and the 

 cross-vein, and, in fresh specimens, by the club-shaped lobes of 

 the male forceps. The teeth on the under side of the ungues are 

 very small and difficult to perceive. The last tarsal joint is some- 

 what incrassated in the male and the interval between it and the 

 preceding joint is excised. There is a European species, the name 

 of which I do not know, and which closely resembles D. haeretica. 



13. I>. lialterata, n. sp. %. — Fusca; rostrum, palpi et antennae 

 nigra ; halteres longiusculi ; alas pallide infuscatse, iinmaculatse, stig- 

 mate obscuriore ; venula transversa subcostalis ab apice venae auxiliaris 

 longitudine stigmatis remota. 



Brownish ; rostrum, palpi, and anteDnse black ; halteres rather long ; wings 

 tinged with pale brownish, immaculate, stigma darker ; the subcostal 

 cross-vein is removed from the tip of the auxiliary vein at a distance 

 equal to the length of the stigma. Long. corp. 0.3. 



Head brownish, somewhat sericeous with yellowish ; antennae 

 and palpi black. Thorax dull brown, hardly shining above; 

 humeral region sericeous with yellowish; the usual stripes con- 

 fluent ; pleurae brown, sericeous with grayish below thcroot of 

 the wings and that of the halteres ; scutellum and metathorax 

 brown, sericeous with gray ; halteres comparatively long, infus- 

 cated, their root pale. Abdomen brown, the genitals but little 

 paler. Eeet brown, coxae brownish-yellow ; tarsi almost black. 

 Wings tinged with pale brownish ; tip of the auxiliary vein nearly 

 opposite the origin of the praefurca ; the subcostal cross-vein re- 

 moved back of this tip at a distance nearly equal to the length 

 of the stigma ; marginal cross-vein at the tip of the first longi- 

 tudinal vein ; discal cell closed. 



