18 MISC. PUBLICATION 174, U.S. DEPT. OF AGRICULTURE 



several subsequent writers, but so far as known they have never been 

 verified. Kulagin (1898) identified P. herrickii as a parasite of an 

 Agromyza in Russia, basing the identification upon a larva. That 

 this record was almost certainly an error was pointed out by Marchal 

 in 1906. Marchal gave it as his opinion that the larva figured by 

 Kulagin was probably a chalcidoid instead of a Platygaster. The 

 writer has seen no specimens of P. herrickii from Europe. There 

 appears to be no reason why it should not occur there, but if it does its 

 presence has not yet been proved. 



IMPORTANCE 



Although generally distributed, this species is probably not so 

 important a parasite of the hessian fly as either P. hiemalis or P. 

 zosine. According to Hill and Smith, it was responsible for an 

 average of only 0.08 percent parasitization over a period of 10 years 

 in Maryland, Virginia, and Pennsylvania. They state that it is 

 more prolific farther south. In Oregon, according to an unpublished 

 statement by L. P. Rockwood, the species was responsible for a 15 

 percent parasitization of the spring generation of the fly in 1930. 



PLATYGASTER ERROR Fitch 



(Fig. 4) 



Platygaster error Fitch, N.Y. State Agr. Soc. Trans. (1860) 1861: 818, pi. i, 

 fig. 4 (reprinted in Insects of New York, Rpt. 6: 76, 1865) ; Packard, Rpt. U.S. 

 Ent. Comm., Bui. 4: 21, 1880, and U.S.Ent.Comm.Rpt. 3: 219, 1883; Forbes, 

 111. State Ent. Rpt. 14 : 44, 1885 ; Ashmead, Canad. Ent. 19 : 132, 1887 ; Cresson, 

 Svnopsis of the families and genera of the Hymenoptera of America, north of 

 Mexico ... p. 250, 1887; Smith. Insects of New Jersey . . ., p. 42, 1890; 

 Fouts, U.S. Natl. Mus. Proc. 63 (art. 15) : 27, 60, 1924. 



Anopedias error Riley, U.S.Dept.Agr., Div. Ent., Insect Life 4: 125, 1891; 

 Ashmead, U.S. Natl. Mus. Bui. 45: 291, 1893; Dalla Torre, Catalogus hymen- 

 opterorum . . . , v. 5, p. 482, 1898 ; Smith, Insects of New Jersey . . . , p. 546, 

 1900; p. 652, 1910; Viereck, Conn. State Geol. and Nat. Hist. Suryey Bui. 22: 

 533, 1916; Britton, Conn. State Geol. and Nat. Hist. Survey Bui. 31: 326, 1920: 

 Kieffer, Das Tierreich, v. 48, p. 703, 1926. 



DESCRIPTION 



In size and general appearance Platygaster error resembles P. 

 hiemalis, but it may be distinguished from that species by the dis- 

 tinct parapsidal grooves, the more triangular and less convex scu- 

 tellum, the shallower groove between scutellum and mesoscutum, the 

 more receding temples, and the differently shaped abdomen of the 

 female. It differs from P. zosine by the same characters as from 

 hie?nalis, and in addition by the much smoother head. From her- 

 rickii it differs in the smaller size and less convex scutellum and also 

 in the lack of distinct sculpture on the mesoscutum. 



Female. — Length 1.20 to 1.30 mm. Head transverse, about as wide as the 

 thorax, distinctly narrowing behind the eyes, the temples receding ; head behind 

 the vertex weakly shagreened, elsewhere mostly smooth and polished; ocelli 

 in a low triangle, the lateral ones a little more than their own diameter from 

 the eye margin ; head viewed from in front very slightly broader than long ; 

 malar space short, not more than one fourth as long as the eye ; a few hairs on 

 mandibles and around the oral region, the rest of head practically bare. 

 Antennae inserted at the clypeus, 10- jointed, covered with short pubescence; 

 scape subfusiform, about equal in length to the 5 following joints ; pedicel more 

 than twice as long as thick, distinctly a little shorter than the 2 following joints 



