NATURAL SCIENCES OF PHILADELPHIA. 235 



L. aprilina. Cinerea, pedibus subfuscis, basi pallidis ; alis ad costam 6 

 vel 7 raaculatis ; venis transversis, nebulosis; long. lin. 2. 



Head cinereous ; palpi black ; antenna? clothed (in the ^) with a dense pu- 

 bescence, dark tawny ; two basal joints brown. Thorax cinereous ; praescutum 

 yellowish, with indistinct stripes, the intermediate one capillary ; halteres pale ; 

 feet dark tawny, coxae and base of femora pale. Abdomen cinereous ; the homy 

 appendages of the ^ forceps short, stout and obtuse; one of them with a deep 

 notch at the tip, (fig. 25 and 25a.) Wings with seven brown spots along the 

 anterior margin ; the first near the base ; the third is sometimes connected with a 

 nebulosity on the supplementary cross-vein and with a large round spot at the tip 

 of the axillary vein ; the fourth is sometimes connected with a nebulosity along 

 the central cross-veins ; the fifth situated at the tip of the subcostal vein is the 

 largest of all, and nearly square ; the sixth and seventh are at the tips of both 

 branches of the radial vein; the other veins have likewise small spots at their 

 tips ; the great cross-vein is clouded, as well as the other cross-veins ; base of 

 the wing, subcostal and pobrachial veins, yellow. 



Two c? specimens. Washington, in April, (nob.) 



4th Section. 



Wings like Meig. i. tab. vi. f. 2, elongated, narrow. Antenna of the $ much 

 longer than head and thorax together, filiform ; joints subcylindrical, elongated, clothed 

 with a short, dense pubescence, and with moderately long verticils ; antennas of 

 the 9 a little shorter than those of the $ ; pubescence indistinct, but verticils 

 long. 



This section is allied to Section 2d (I d i o p t e r a) by the structure of the tf 

 antennae, and to Section 5tb by the neuration of the wings and the whole habi~ 

 tus of the body. 



L. tenuipes. Brunnea, humeris, pleurisque silaceis ; alis infuscatis ; 

 long. lin. 3 4. 



Limnobia tenuipes Say, Jour. Acad., Phil. iii. p. 21, 3. 



L. humeralis Wied., Auss. Zw. i. p. 38, (not L. humeralis Say.) 



Proboscis ochraceous ; palpi black ; antennae black, base paler, front black, 

 with a cinereous reflection. Thorax ochraceous, prasscutum shining, more or 

 less brown in the middle ; scutum, scutellum and metathorax also brown in the 

 middle ; halteres infuscated at tip ; feet dark tawny, pale at base ; coxa? ochra- 

 ceous. Tergum brownish, venter paler. Wings with a brownish tinge, stigma 

 elongated, brown, sometimes very pale; neuration exactly like Meig. i. tab. vi. 

 f. 2. 



Twelve $ and 9 specimens from Washington, in June, and Savannah, Ga., 

 in April, (nob.) 



N. B. Say's descriptions of L. tenuipes and L. humeralis are so 

 much alike that the choice between them was somewhat difficult in identifying 

 the present species. Still the words in the description of L. tenuipes "an- 

 tenna? long," and " wings dusky " determined my choice. Wiedemann took 

 both for synonyms ; but Say denies this synonymy in a manuscript note, which 

 still exists in a copy of Wiedemann's work, which he had used. 



5th Section. 

 (Typical Limnophilae.) 



Neuration of the wings like Meig. i. tab. iv. f. 20, and tab. vi. f. 2 or 3 ; no 

 supplementary cross-veins; antennae hardly reaching or not reaching much be- 

 yond the base of the wings ; basal joint cylindrical, elongated ; the second 

 short; joints of the flagellum subcylindrical or elliptical, with moderate, some- 

 times long, verticils. Feet long, moderately slender. 



L. adusta. Ferrugineo-flava, fronte cinerea, thorace nitido, alis flaves- 

 centibus, ad apicem infuscatis, stigmate fusco ; long. lin. 3^ 4. 



1859.] 



