214 PROCEEDINGS OF THE NATIONAL MU8EUM. vol.49. 



sheath and different sculpture of the head, as the following description 

 will show : 



Female. — Length 5 mm. Anterior margin of the labrum obtusely 

 pointed; clypeus broadly, arcuately emarginate, the lobes acute; 

 supraclypeal area triangular in outline, supraclypeal foveae con- 

 fluent with the antennal foveae, middle fovea elongate, breaking 

 through the crest; oceUar basin with the lateral walls obsolete, the 

 lower walls sloping; as indicated, the basin is pentagonal in outline 

 and meets dorsally a little behind the anterior ocellus; a shining, 

 elongate fovea in front of the anterior ocellus; antennal furrows deep, 

 but not extending much beyond the posterior ocelli ; postocellar line 

 slightly longer than the ocellocular line; postocellar furrow deep, well 

 defined, terminating at the inner margins of the ocelli; joostocellar 

 area flat, defined laterally by a line-hke furrow, rectangular in outline 

 and two and one-half times as broad as the cephal-caudad length; 

 antennae stout, slightly tapering apically, third and fourth joints 

 subequal; mesoscutum shining with a few poorly defined punctures; 

 scutellar appendage with setigerous punctures ; stigma gently rounded 

 on the lower margin; upper and lower discal cells of equal length; 

 sheath broad, straight above, tapering from an obtuse apex to a 

 broad base, densely clothed with long, pale hairs; inner tooth of 

 claws shorter than the outer. Black; mandibles except piceous 

 apices, clypeus, labrum, palpi, supraclypeal area, posterior margins 

 of the pronotum and tegulfie, fulvous; posterior orbits rufo-piceous; 

 legs below the coxae fulvous, the posterior tarsi infuscated; wings 

 hyaline, irridescent; venation dark brown; stigma almost concolorous, 

 pale brown. 



Male. — Length 3.5 mm. Hypopygidium obtusely pointed apically, 

 otherwise the structure agrees very well with the above description 

 of the female. Color of the male is the same as the female, except 

 that the posterior tarsi are more infuscated and the hypopygidium 

 is pale. 



Toronto, Ontario. Described from three females (one, type) and 

 four males (one, allotype) which were reared from galls from the 

 petiole of Salix humilis, material collected and reared by A. Cosens, 

 for whom the species is named. This gall is well described by Cosens, 

 and the description need not be repeated here. 



Type.— C^t. No. 18528, U.S.N.M. 



Family CIMBICIDAE. 



Tribe CIMBICINI. 



The genera belonging to this tribe, as defined in the Proceedings of 

 the Entomological Society of Washington,' may be separated as 

 follows : 



>Vol. 13, 1911, p. 219. 



