210 PROCEEDINGS OP THE ACADEMY OP 



halteres pale, knobs dusky; feet dark tawny, pale at base, brown ring at 

 tbe tip of femora often scarcely apparent ; tips of tibiae and those of tarsi 

 brown. Abdomen cinereous ; $ forceps pale tawny ; its structure like fig. 4. 

 Wings hyaline, faintly tinged with grey ; veins brownish, pale at basis ; costal 

 and subcostal pale ; stigma oblong, pale, distinctly clouded at the cross-vein ; 

 the mediastinal vein joins the costal nearly opposite the origin of the petiole ; 

 sometimes a little before or beyond it : the cross-vein is near its tip ; the great 

 cross-vein is generally a little before the discal areolet ; sometimes it is in one 

 line with the upper discal cross-vein. 



Eleven $ and six 9 specimens. 



Common near Washington in summer. I have also specimens from Mobile, 

 Ala., and Dalton, Ga., (nob.) and Wisconsin, (Mr. Kennicott). 



In one of the specimens the discal areolet, on one wing only, is open. 



In another specimen (a 9 ) * ne second externomedial areolet takes an ob- 

 lique direction and joins the first, forming by this a petiolate areolet. This 

 is the case on both wings. 



D. humidicola. Fusca, abdomine fasciis pallidis, pedibus fuscis, femo- 

 runi apice pallido, alis subcinereis, cinereo nebulosis ; stigmate subquadrato, 

 fumato ; long. lin. 3-3J. 



Proboscis, palpi and antennae black ; joints of the flagellum subglobular, 

 becoming more elongated towards the tip ; verticils moderate ; front and vertex 

 dark cinereous. Thorax tawny ; the stripes brown, moderately distinct, more 

 or less confluent ; humeri yellowish, with a faint yellow, sericeous reflection ; 

 scutum, scutellum and metathorax brown, the first two with more or less 

 yellow spots ; pleurae brown, with pale spots ; halteres pale, knob infuscated; 

 coxae pale ; feet tawny, a pale ring close at the tip of the femora. Abdomen 

 tawny, with pale bands on the incisures ; tf forceps like fig. 3 ; ovipositor 

 of the 9 furruginous. Wings subcinereous, with darker shades of gray at 

 the tip, in the middle of the prsebrachial areolet, in the pobrachial, (along 

 the pobrachial vein) and in the first externo-medial (along the same vein ;) 

 the central cross-vein, all the discal cross-veins and the great cross-vein, are 

 clouded ; there is a pale brown spot at the margin of the petiole ; another, 

 larger and nearly round spot at the junction of the radial and cubital veins ; 

 stigma brown, nearly parallellopipeclal ; the mediastinal vein joins the costal 

 generally a little beyond, sometimes nearly opposite the origin of the petiole ; 

 the cross-vein is near its tip ; the great veinlet is generally a little before the 

 discal areolet ; the color of the veins is brown. 



Washington, Trenton Falls (nob.), Connecticut (Mr. Norton). Common in 

 damp, shady situations, especially in hollows having a spring at the bottom. 

 Compared twelve (<^, 9 ) specimens. One of my specimens has a stump of 

 a vein on the curve of the petiole. 



A variety of this species (consisting, perhaps, of immature specimens?) has 

 no clouds on the wings ; the stigma is brown, as usual. I caught them in 

 numbers at Sharon Springs, N. Y. Such specimens are easily recognized by 

 the pale tip of the femora, which is a very characteristic marl: of the species. 



D. stulta. Fusca, humeris, pleurisque pallidis, alis subcinereis, stigmate 

 pallide cinereo ; long. lin. 2^3. 



Proboscis and palpi black ; antennae black, hardly reaching much beyond the 

 fore-coxae ; joints of flagellum oblong, with moderate verticils ; front and 

 vertex dark cinereous. Thorax yellowish tawny; stripes brown, more or less 

 shining, almost confluent ; intermediate one extending over the collare, and 

 sometimes faintly capillary ; the lateral ones are extended over the scutum ; 

 scutellum and metathorax brown ; halteres infuscated, pale at base ; feet 

 brownish, pale at base. Abdomen brown ; <$ genitalia paler ; the rostriform 

 appendage is small, and has two erect bristles ; 9 ovipositor ferruginous. 

 Wings subcinereous, stigma oblong, pale; veins pale brown; the tip of the 



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