526 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.55. 



Female. — Type. — Length, 7 mm.; antennae, 5 mm.; ovipositor, 2 

 mm. 



In my key to the species of Aenoplex ^ it does not agree strictly with 

 either alternate in the first couplet, the mesoscutum being opaque with 

 dense minute punctures, especially in the posterior middle. It is, 

 however, more closely allied to Aenoplex nigrosoma Cushman than ta 

 any of the other species, differing principally as follows: Stouter, 

 head not distinctly swollen; temples more strongly rounded; malar 

 space scarcely shorter than basal width of mandible; antennae rela- 

 tively longer; propodeum hardly striate above, more irregularly 

 roughened ; areola much wider than long, about half as wide at base 

 as at apex ; inner spur of hind tibia less than one-third as long as basi- 

 tarsus; abdomen but slightly longer than head and thorax; first 

 tergite and second at anterior corners striate, abdomen otherwise 

 sculptured as in nigrosoma; first tergite relatively broader, fully two- 

 thirds as broad at apex as long ; the spiracles prominent ; evopositor 

 little more than half as long as abdomen. 



Black, and colored like nigrosoma^ except that the antennae and 

 entire hind tibia and tarsus are fuscous, the tegulae reddish, and the 

 legs generally more j^ellowish than reddish. 



Type.— Cat. No. 21630, U.S.N.M. 



No locality. 



A paratype female that lacks abdomen, wings, tips of antennae, and 

 most of the legs agrees perfectly in head and thoracic characters with 

 the type. The third specimen, reared from Callosamia promethea 

 under Bureau of Entomologj^, No. 423 ^, differs from the type princi- 

 pally in having the legs and antennae darker and in having the areola 

 distinctly emarginate behind. 



Genus ISADELPHUS (Foerster) Roman. 



Roman ^ synonymizes this genus with Cecidonomus Bridgman, and 

 includes inimicus (Gravenhorst) and nigriventris (Thomson). The 

 former was designated by Viereck^ as the genotype of Isadelphus. 

 According to the priority rule Isadelphus Foerster should have been 

 used as the generic name. Viereck ^ synonymizes the two in the latter 

 manner. 



Specimens of nigriventris (Thomson) and inimicus (Gravenhorst) 

 determined by Roman are in the United States National Museum col- 

 lection. These specimens disagree somewhat with Foerster's char- 

 acterization of the genus in that the middle lateral areas of the propo- 

 deum are not especially carinately prominent at the apex. In every 

 other way, however, they do agree. The swollen head, apically com- 



» Proc. U. S. Nat. Mus., vol. 53, 1917, p. 459. 



2 Naturn. Untersuch. des Sarekgebriges, vol. 4, 1909, p. 233. 



8 Bull. 83, U. S. Nat. Mus., 1914, p. 76. 



