500 
[March 
cated and the hind tibise brown. Wings hyaline, veins rather fine, the principal 
veins generally brownish, sometimes even in the darkest specimens yellowish 
hyaline. Areolet large, distinct. Radial area closed, about twice as long as 
wide, with the areolet placed ^ of the way from its base.—Length % .07—.10 
inch. 9*0'^—.14 inch. 
Thirteen S , thirty-one 9 • Came out from the gall' q. potlagrse n. sp. 
May 10—15, and very numerous specimens subsequently. I ascer¬ 
tained by keeping the pale 9 9 four days alive and exposed to the 
light, that the pale color did not become darker, and I noticed very 
dark 9 9 that must have hatched out within 24 hours. Similar va¬ 
riations occur also in C. q. spongifica^ whence we may infer that the 
rust-red color there is not due to immaturity. Comes very near to 
S. ligmcola 0. S., which was bred from a woody gall on q. palustris, 
but dij0Fers as follows :—l.s^. That species, described from “ numerous 
specimens,” has its ground color always yellow.” 2nd. The last 
joint 9 antennae in rhoditiformis never shows ^Hwo slight sub-divisions” 
and not often even one. 8 re?. The collare in rhoditiformis always 
has a large dorsal black spot, instead of being immaculate as is spe¬ 
cially mentioned of lignicola. ^th. Nothing is said under lignicola of 
the very remarkable “ ventral valve” found in rhoditiformis .—This 
insect is of a much more robust habit than either S. oneratus or S. 
mendax^ and as the 9 antennae have one joint less than in those two 
species, and the ventral valve is so remarkably developed, it might 
perhaps form a separate genus. Since, however, in Cynipidae there are 
already far too many imperfectly characterized genera, I prefer to refer 
it provisionally to Sgnerges. 
Rock Island^ Illinois Feb. 15, 1864. 
ERRATUM. 
Page 459, line 8 from bottom, for ‘‘Dorcatoma” read ‘‘ Decatoma.” 
