NATURAL SCIENCES OP PHILADELPHIA. 237 



short and but slightly oblique ; radial vein conspicuously arcuated before its fork- 

 ing, (hence the name of the species.) 



One $ and five $ Trenton Falls, (nob.) 



L. imbecilla. Fusco-silacea, thorace unicolore, antennis fuscis, basi 

 flagelli pallida, verticillis longis ; petiolus longus, venoz radiali longitudine ceqaus ; 

 long. lin. 3^ 4. 



Front cinereous, palpi infuscated, antennae brownish, pale at the base of the 

 flagellum, with long verticils. Thorax brownish yellow ; pleurae and metatho- 

 rax slightly hoary ; halteres pale, slightly infuscated ; feet pale tawny ; tips of 

 tarsi brown. Abdomen tawny ; tip pale ; 9 ovipositor long. Wings pale 

 cinereous, stigma more or less pale fuscous ; petiole about as long as the radial 

 vein, forming a straight line with the portion of this vein which is anterior to 

 the fork ; the stigmatical cross-vein is beyond the middle of the stigma, very 

 near the origin of the radial fork and about the middle of the distance between 

 the tip of the costal vein and the anterior end of the stigma ; the central cross- 

 vein forms a straight line with the cross-vein, separating the cubital area from 

 the praebrachial, (which cross-vein is, in fact, the anterior portion of the cubital 

 vein.) 



Four $ and seven $ specimens. Trenton Falls, N. Y., Virginia and Georgia, 

 (nob.) Illinois, (Mr. Kennicott.) 



This species is very like L. t ox on e u r a in its coloring, but is easily dis- 

 tinguished by the different neuration of the wing. 



The thorax of the normal specimens is not shining ; the front is slightly cinere- 

 ous ; but among the specimens which I collected in Georgia there are two or 

 three with a shining thorax and a brownish yellow front. They agree in all 

 other characters, and I hardly think that they form a distinct species. 



L. brevifurca. Fusca, thorace cinerascente, alis subcinereis, areola 

 petiolata brevissima ; long. lin. 2f . 



Head cinereous ; antennae and palpi fuscous. Thorax cinereous, slightly 

 yellowish on the preescutum ; an obsolete, pale brown, double stripe along its 

 middle ; halteres pale at base ; knob slightly infuscated ; feet moderately 

 hairy, dark tawny, slightly infuscated at the tips of the femora and tarsi ; 

 coxae and base of femora pale. Abdomen brownish ; $ forceps pale. Wings 

 subcinereous, stigma slightly infuscated ; petiolated areolet from four to six 

 times shorter than its petiole ; the radial vein, before its forking, forms a 

 straight line with the petiole ; the portion of the cubital vein anterior to the 

 central cross-vein is very short, perpendicular to the radial vein, and in one 

 line with the central and upper discal cross -veins ; the mediastinal vein joins 

 the costal very near the stigma ; the mediastinal cross-vein is at a short dis- 

 tance from their junction. 



Washington, in April, Cnob.) Eight .$ specimens. 



L. areolata. Pallide silacea, alis ad basin pallide flavescehtibus, tarso- 

 rum apice infuscato, area discoidali elongata ; long. lin. 2| 3. 



Pale ochraceous yellow, antennae, except the basal joint, slightly infuscated, 

 with moderately long verticils ; halteres pale, very slightly dusky ; tarsi in- 

 fuscated, especially at the tip. Wings with a very slight cinereous tinge, 

 yellow at the root ; costal, mediastinal and subcostal veins yellow ; the other 

 veins brown, with a short pubescence ; stigma pale, sometimes very slightly 

 infuscated ; the mediastinal cross -vein is removed from the tip of the medias- 

 tinal vein at a distance a little longer than the great cross-vein ; stigmatical 

 cross-vein in the middle of the stigma and also in the middle between the tip 

 of the subcostal vein and the origin of the radial fork ; discal areolet about 

 equal in length to the second externomedial areolet, and about twice as long 

 as in most of the other species ofLimnophila. 



Thirteen ^ and 9 specimens. Trenton Falls in June, and Maryland in 

 May, (nob.) 



1859.] 



