66 PROCEEDINGS OF THE NATIONAL. MUSEUM vol.79 



25. DECATOMA NIGKICEPS var. EXCRUCIANS Walsh 



Walsh ^ recognized this variety, the specimens of which, he states, 

 " differ from the normal form of nigriceps only in the scape of the 

 antennae being dull rufous instead of brown-black. The antennal 

 groove is black." He had three males and one female reared July 2 

 from the gall of the cynipid, Andrieus seminator Harris \G allirhytis 

 seTTiinator (Harris)]. None of this material is at hand. The ex- 

 treme variation of color in this species, even in lots obtained at one 

 time from the same locality and hosts, is so great that any color limit 

 set up for varieties has no value. I am compelled to disregard this 

 variety of Walsh. 



26. DECATOMA SUBIMMACULATA Girault 



Decatoma suhimmaculata Girault, Journ. Ent. and Zool., vol. 9, p. 11, 1917. 

 Decatoma autumnalis Girault, Proc. U. S. Nat. Mus., vol. 58, p. 209, 1920. 

 Decatoma compressa Girault, Proc. U. S. Nat. Mus., vol. 58, pp. 209-210, 1920. 



Nearest to D. querci-lanae (Fitch) in its mostly yellow body, but 

 is distinguishable by its lack of most of the black dorsal markings 

 on the thorax present on Fitch's species. D. subimm/wulata is, in 

 general, somewhat larger. 



Female. — Length 2.5 to 4.9 mm., mostly 3 mm. or longer, moder- 

 ately robust, colors chiefly golden or honey yellow, in small part 

 black; head yellow but space within ocelli, and forward into antennal 

 scrobe more or less, and occiput about halfway from foramen to eyes 

 behind, black ; scape concolorous with head or lined with brown on 

 basal part of outer edge, pedicel feebly infuscate above mostly on 

 basal two-thirds, flagellum light brown ; pronotum usually immacu- 

 late golden yellow, sometimes darkened behind by black on prescutum 

 beneath or occasionally on hind part of pronotum itself ; mesothorax 

 concolorous with pronotum, prescutum at times immaculate, but 

 more often a subtriangular patch of black on disk, which extends 

 forward broadly under pronotum and tapers caudad, front edge of 

 scutel at times faintly black, and a mere tinge of black longitudivially 

 on the middle and sometimes small areas black on lower edge of 

 axillae near tegulae ; metanotum yellow, propodeum black on middle 

 half in front, and groove sometimes narrowly, sometimes broadly 

 black, sterna of thorax not extensively black ; legs immaculate, light 

 yellow, tibiae approaching stramineous-yellow, tarsi still more nearly 

 so ; stigma as on other species, with only a rudiment of submarginal 

 band; peduncle black, abdomen ochreous-yellow to golden yellowish 

 brown, usuall}' a narrow, irregular longitudinal mid-dorsal black 

 band without pronounced lateral projections on the segments. 



Head slightly variable in dimensions, from one-twentieth more 

 than half longer than wide to about half as long as wide, face mod- 



Amer. Ent. and Bot., vol. 2, no. 10, p. 301, 1870. 



