NATURAL SCIENCES OF PHILADELPHIA. 207 



is longer than the antennae ; it consists of a linear, very long lingua, and au 

 equally long labium, divided from the base in two branches ; palpi very short, 

 near the tip of the proboscis, but at a considerable distance from the tip of the 

 haustellum.* 



The other characters of the genus agree with those of the 3d section, (Dicra - 

 n o m y i a Sleph.) The forceps of the male has the same structure ; the habits 

 seem to be the same, both genera being found in damp situations. 



This genus was formed by Haliday, in 1833, on a European species, the only, 

 I think, at present known from that part of the world. The American continent 

 seems to be more abundant in Geranornyiae. Dr. Loew published six species 

 from Brazil, Chili, and the West Indies, and Mr. Walker one from Brazil. I 

 have found three species within the United States. 



Macquart's genus A p o r o s a, (established in 1838), is identical with G e r a - 

 n o m y i a Halid. 



Analytical Table. 



1. Wings spotted, G. rostrata Say. 



Wings not spotted, 2 



2. Thorax cinereous, with three black stripes ; the mediastinal vein joins the 

 costal nearly opposite the origin of the petiole. G. diversa ?wb. 

 Thorax tawny, with brown stripes ; the mediastinal vein joins the costal at 



about the middle of the distance between the origin of the petiole and the tip 

 of the subcostal vein. G. comniunis nob. 



G. rostrata. Alis fusco maculatis et nebulosis ; long. lin. 3. 



Say, Journ. Acad. Phil. iii. 22, 6. 



Wiedem. Auss. Zw. i. 35, 20. 



Front and vertex cinereous ; proboscis and antenna brown. Thorax gray with 

 more or less distinct brown stripes ; the intermediate one appears sometimes 

 slightly capillary ; humeri and pleurae tawny with a hoary reflection ; scutellum 

 and metathorax brown, hoary ; halteres pale yellow with a brown knob ; feet 

 tawny, tips of the tibia; black, thickly clothed with very short black hairs, and 

 appearing for this reason slightly clavate ; tips of tarsi infuscated. Abdomen 

 brown, venter paler. Wings with five nearly square brown spots along the 

 anterior margin ; cross-veins and tips of all the veins along the apex and the 

 posterior margin clouded with pale brown. 



Four (J 1 9 specimens. Washington (uob.) Mass. (Harris' Catal. Ins. Mass.) 

 I have caught the same species in Cuba. 



G. communis. Pallide fusca, thorace fusco-vittato, alae hyalinre stigmate 

 ovali, obscuro ; long. lin. 1\ 2f. 



Front and vertex cinereous, occiput tawny ; antennae brown, under side of the 

 1st joint tawny; palpi and proboscis brown, basis of the latter pale. Thorax 

 tawny, with three more or less dark brown stripes ; pleurae yellowish tawny; 

 metathorax brown with a hoary reflection ; halteres blackish, with a pale base ; 

 feet tawny, tips of femora, tibiae and tarsi brown. Abdomen brown, mar- 

 gins of segments pale ; venter paler. Wings hyaline, slightly cinereous, with 

 a pale brown oval stigma ; the tip of the subcostal vein forms a curve joining 

 the radial ; the stigmatical cross-vein is a little before their junction ; the medi- 

 astinal vein joins the costal at about one-third of the distance between the origin 

 of the petiole and the tip of the subcostal vein. 



Five <$ and 3 ^specimens. Washington (nob.) Upper Wisconsin River, (Mr. 

 Kennicott). 



G. diversa. Thorace cinereo, vittis tribus nigris,.alas subhyalinse, stig- 

 mate pallide fusco ; long. lin. 1\ 2f . 



1859.] 



f I disiinguish here the proboscis from the haustellum, according to the acceptation of 

 t;hs word laid down in Illiger's Terminology. 



