74 
Three males, one from Lanskig, Mich., labeled " Lombardy poplar," 
and two specimens bred from larvae on willow by Mr. Dyar (Coll. U. S. 
Nat. Mus.). 
Mr. Dyar, for whom I determined as above some bred males, thinks 
this may prove a seasonal form of ventral is (Trans. Am. Ent. Soc, 
xxu, 1805, p. 305). Mr. Dyar's specimens were obtained in New York 
on Salix, and, together with the types, present what seem to be .n'ood 
specific differences from ventralis. 
48. Pteronus dubius new species. 
Male. — Length 5.5 mm.; clypens broadly emarginate, almost trun- 
cate; frontal crest very large, strongly angled anteriorly, lateral walls 
of basin tapering rapidly posteriorly; antenna! fovea narrow, breaking 
slightly through crest; antennae robust, flattened, joints 4 and 5 a little 
longer than 3j venation about normal; second recurrent interstitial or 
nearly so in fore wings and the outer veins of discal cells interstitial 
in hind wings; stigma rather narrow, rounded on lower margin; pro- 
cidentia short, not very broad, apex rounded; claws deeply divided, 
rays subeqnal. Color black, shining: clypens and other mouth parts 
and extending to eyes whitish; narrow line on venter of abdomen, 
including all of hypopygium and the legs, ferruginous yellow; bases 
of coxae black: wings hyaline; veins and stigma brown. 
One male. Welleslev, Mass., March 20. (Coll. V. S. Nat. Mus.) 
40. Pteronus stigmatus Norton. 
1861. Nematus stigmatus | Harris* Norton. Proc. Host. Soc. Nat. Hist., vm, p. 161. 
lstiT. Nematus stigmatus Norton. Trans. Am. Ent. Soc, i, p. 221. (Cat., etc., p. 83.) 
Female. — Color greenish Lnteons; body short and stoat; antennae moderate, the 
two basal joints black; a small black spot about each of ocelli ; clypens hardly 
emarginate; labrnm angnlate, hairy; part of mesothorax, the metathorax, the first 
seven segments of tergam and ovipositor sheaths, and a spot on pleura below wings 
black; legs pale; tips of tarsi and claws blackish; wings hyaline; stigma and costa 
pale green. 
One female. Massachusetts. (Harris's Coll.) 
• It has the size and form of K. monochroma. 
50. Pteronus monochroma Norton. 
1801. Nematus monochroma (Harris) Norton. Proc. Bost. Soc. Nat. Hist., vm, 
p. 161. 
1867. Nematus monochroma Norton. Trans. Am. Ent. Soc., I, p. 221. (Cat., etc., 
p. 83.) 
Female. — Color honey yellow; body stout; antenna? wanting, except two basal 
joints, which are color of body; ocelli black, set in an irregular depression; clypens 
retracted, crenate; labrnm angnlate; face immaculate; teguhe, collar, venter, and 
coxa' paler than rest of bodj"; pleura dark, almost piceus; legs color of body; 
wings hyaline ; stigma and costa pale yellow. 
One female. Massachusetts. (Harris's Coll.) 
Resembles N. luteus, of Europe. 
