6 MISC. PUBLICATION 17 4, U.S. DEPT. OF AGRICULTURE 



Proc. 53: 256, 1917; Walton, U.S.Dept.Agr. Farmers' Bui. 1083: 12, 1920; 

 McColloch, Kans. Agr. Expt. Sta. Tech. Bui. 11 : 70, 71, 1923. 



Platygaster minutula Dalla Torre, Catalogus hymenopterorum . . ., v. 5, 

 p. 474, 1898 (for minutus Lindeman, not Zetterstedt) ; Kieffer, Das Tierreich, 

 v. 48, p. 828, 1926 ; Yaroslavtzev and Novinenko, Kharkov Regional Agr. Expt. 

 Sta., Ent. Otd. no. 7, 1927 (abstract in Rev. Appl. Ent. (A) 16: 177, 1928) ; 

 Meyer, Rpt. Appl. Ent. Leningrad 4 : 241, 1929. 



Polygnotus minutus Pospjelov, Illus. Ztschr. Ent. 5: 261, figs. 1 and 2, 1900; 

 Spassky, Ann. Don Polyt. Inst. Novotcherkassk 5 (1) : pt. 2, 1916 (abstract in 

 Rev. Appl. Ent. (A) 5: 29, 1917). 



Polygnotus sp. Ainslie, Ent. Soc. Wash. Proc. 10 : 14, 1908 ; Pettit, Mich. Agr. 

 Expt. Sta. Bui. 258 : 72, 1910. 



Polygnotus minutulus Blunck, Ztschr. Angew. Ent. 18 : 585, 1931. 



DESCRIPTION 



Platygaster hiemalis may be distinguished at once from P. herrichii 

 Packard and P. error Fitch by its lack of distinct parapsidal grooves. 

 In having these grooves very poorly developed or almost absent it 

 agrees with P. zosine, but it differs from that species in that the front 

 of the head below the ocelli is mostly smooth and shining, the front 

 wings are barely twice as long as the abdomen and perfectly hyaline, 

 and the scutellum is distinctly broader than long, without marginal 

 carinae. It also superficially resembles Trichacis remulus but is sep- 

 arated at once by the absence of any tuft of hairs on the scutellum, 

 by the poorly developed parapsidal grooves, and by antennal charac- 

 ters. 



Female. — Length 0.75. to 1.3 mm. Head as viewed from above twice as broad 

 as long ; occiput weakly margined ; behind the vertex finely transversely rugu- 

 lose; head viewed from in front a little broader than high; ocelli in a low 

 triangle, the lateral ocelli about as far from the eye margins as from the 

 front ocellus ; vertex nearly smooth but usually with faint reticulate sculpture 

 around the ocelli; upper part of frons usually perfectly smooth, the lower 

 half usually with very weak, more or less oblique aciculations ; eyes oval, more 

 than twice as long as the malar space; whole head bare except for a few hairs 

 on mandibles and around the mouth. Antennae 10-jointed, inserted at the cly- 

 peus ; scape extending a little above the vertex, about as long as the 5 follow- 

 ing joints ; pedicel about as long as the 2 following joints ; first and second 

 flagellar joints unequal, the first shorter and more slender than the second 

 but longer than broad ; the second usually a little less than twice but sometimes 

 twice as long as broad; the third about as long and nearly or quite as broad 

 as the second, broadest near the middle ; the fourth a little longer than the 

 third, narrow at base but much broader at apex; the fifth, sixth, and seventh 

 subequal, each about as long as the fourth but usually a little thicker and not 

 broader at apex than at base ; apical joint ovate, about one and one half times 

 as long as the preceding joint; flagellar joints (under high magnification) with 

 a few hairs, those hairs at the lower apical angle of each joint somewhat 

 coarser than elsewhere and pale ; last 5 joints forming the club. Thorax ovoid, 

 highly convex above ; prothorax very finely and weakly reticulated ; mesoscutum 

 nearly smooth but with some faint reticulations anteriorly; parapsidal grooves 

 absent or very faintly indicated posteriorly ; scutellum convex, broader than 

 long, immargined, smooth or nearly so, its sides covered with whitish pile ; 

 the transverse groove separating scutellum from mesoscutum deep and broad 

 but partially interrupted in the middle ; mesopleura smooth, polished, bare ; 

 metapleura evenly clothed with white pile; propodeum short, with a groove 

 medially which is bordered on each side by a carina, pilose except in the groove. 

 Wings veinless ; fore wing about twice as long as the abdomen ; discal ciliation 

 not uniform, a triangular area corresponding to the basal cell practically bare ; 

 marginal cilia very short; hind wing nearly bare at base, ciliated beyond the 

 booklets. Legs normal. Abdomen a little longer than thorax and about as 

 broad as thorax, subovate; first tergite more than twice as broad as long 

 and longitudinally striated ; second tergite bare, comprising about two thirds of 

 the total length of abdomen, mostly smooth and polished but with an elongated 



