NATURAL SCIENCES OF PHILADELPHIA. 209 



paenultimus et ante-paenultimus flavi ; praescutum brunneopictum ; alae fusco- 

 niaculatae ; long. lin. 3-3. 



Front and vertex cinereous ; proboscis and palpi brown ; eyes almost contig- 

 uous, in living specimens dark green above and violet below ; antennae' black ; 

 penultimate and ante-penultimate joints yellow; flagellum moniliform, its joints 

 reniform. Thorax yellowish brown, sericeous when viewed in a certain light ; 

 the thoracic stripes, which are dark brown, become distinct on the posterior 

 part of the praescutum only ; the anterior part is occupied by several brown 

 lines and spots ; a brown stripe on the pleurae, running from the collare back- 

 wards; another one runs along the coxae; halteres tawny, with a dusky spot 

 on the knob ; feet tawny ; coxae and basis of femora pale ; tips of femora, tibiae 

 and tarsi brown. Abdomen dark tawny ; margins of segments brown; (-^for- 

 ceps like figs. 8 and 9. Wings slightly brownish, with five or six brown spots 

 along the anterior margin ; cross-veins and tips of longitudinal veins clouded ; 

 the intervals between the veins also slightly clouded. 



Washington, in May and August (nob.) 6 tf, 9 specimens. 



R. fid el is. Fusca, antennis fuscis, moniliformibus, subpectinatis, alis 

 fusco-maculatis et nebulosis ; length 3 lin. 



Head, proboscis, palpi and antennae fuscous ; the latter moniliform, subpec- 

 tinated. Thorax dull brown, slightly hoary on the pleurae ; stripes indistinct ; 

 halteres pale ; femora pale yellow, brown at the tip ; tibiae and tarsi brown. 

 Abdomen brown; $ genitals paler. Wings pale brownish, except the region 

 round the stigma and a narrow margin at the tip, which are hyaline; stigma 

 brown; brown clouds at the origin of the petiole, the mediastinal cross-vein 

 and the origin of the fork ; discal and great cross-veins also slightly clouded. 



One $ specimen from Sharon Springs, N. Y. 



'id Section. 



Dicranomyia S'eph. 



Body slender; feet long and slender; wings narrow ; joints of the antennas 

 except the basal ones, oval-oblong, with short or moderate verticils, inserted 

 about the middle of the joint; the ^ forceps (see the figures 3, 4 and 5 of the 

 plate) consists of two soft, moveable, ellipsoidal or subreniform lobes, each 

 being armed on the inside with a short, curved, horny appendage having more 

 or less the shape of a bird's beak (I call it rostriform appendage) ; another 

 horny, long, slender, arcuated appendage {falciform appendage), is closely ap- 

 plied to each lobe; a linear, slightly curved anal style below those lobes. 



The neuration of the wings in the different species of this section is very 

 uniform (almost like Meig. i. tab. vi. fig. 5); some difference may be found only 

 in the position of the mediastinal vein and its cross- vein, and in the presence or 

 absence of the discal areolet. Its absence occurs very frequently ; it is some- 

 times a good specific character, and sometimes only an occasional variety. 



The habits of the species seem to be aquatic ; the larvae probably live in 

 water or mud ; the perfect insects are always found in damp situations. 



This generic name appeared for the first time in J. F. Stephens's Catalogue 

 of British Insects in 1829, and afterwards in Curtis' 's Guide in 1837. I am not 

 aware of any definition of it having ever been published. 



D. liberta. Cinerea, proboscide, palpis et antennis nigris, thorace vittis 

 fuscis ; alae subhyalinae, stigma pallidum, juxta venulam trans versalem infus- 

 catum ; long. lin. 2-3. 



Proboscis and palpi black ; front and vertex cinereous ; antennae black, ver- 

 ticillate with hairs of moderate length. Thorax cinereous ; intermediate stripe 

 broad, fuscous, well defined, capillary (capillarity indistinct in some speci- 

 mens ;) lateral stripes abbreviated before and extended over the scutum behind ; 

 a short oblique brown line runs from the intermediate stripe towards a deep 

 puncture near the humerus ; scutellum slightly tawny on the margins ; 



1859.] 16 



