170 PROC. ENT. SOC. WASH., VOL. 20, NO. 8, NOV. 1918 



Type. Cat. No. 3480 U. S. Nat. Mas. 



Distribution. Known only from the unique female type which 

 was reared from larvae collected on larch at Jefferson, New 

 Hampshire. 



Subgenus Hemichroa Stephens. 



Hemichroa Stephens, Illustr. Britt. Ent.. Mandib., vol. 7, 1835, p. 55, no. 

 18. 



Enages Clistel, Naturg. d. Thierreichs, 1848, p. IX. 

 Leptocercus Thomson, Hym. Scand., vol. 1, 1871, p. 76. 

 Leptocerca Hartig, Fam. Blattw., Holzwestp., 1837, p. 228. 



Key to the Nearactic Species of the Subgenus. 



1 . Females 2 



Males 4 



2. Nervulus in the middle of the discoidal cell; third cubital cell but 



little longer than its apical width; "spot at apex of the posterior 



femora black" pallida (Ashmead) 



Nervulus distinctly beyond the middle of the discoidal cell; third 

 cubital much longer than its apical width; posterior femora 

 black 3 



3. Middle fovea small, deep, circular, with shallow lateral impres- 



sions which extend above the antennal foveae; clypeus with a 

 rather narrow, deep, arcuate emargination, the lobes brpadly 

 rounded apically; second recurrent much before the second in- 



tercubitus americana (Provancher) 



Middle fovea broad, shallow, without lateral impression; clypeus 

 with a deep, subangulate emargination, lobes triangular in out- 

 line; second recurrent close to the second intercubitus dyari Rohwer 



4. Middle fovea broad, shallow; apex of the hind tibiae and all of 



their tarsi black dyari Rohwer 



Middle fovea narrow, elongate, deep; tibiae and tarsi uniformly 

 pale pallida (Ashmead) 



Hemichroa americana (Provancher). 



Dineura americana Provancher, Nat. Canad., vol. 13, 1882, p. 292. 

 Hemichroa americana Konow, Gen., Ins., fasc. 29, 1905, p. 49. 



Type. One female bearing yellow label 639 Public Museum 

 Quebec. 



Notes taken from type and a study of a homotype from New 

 England. The larvae described by Dyar under this name belong 

 to a different species which is described below (see <li/<tri, new 

 species). 



