May 24,1924 Polyembryonic Development of Platygaster vemalis 
839 
(10) Each larva constructs a cocoon in which it transforms to a pupa and later 
an adult parasite. The cluster of cocoons is surrounded by the cuticula of the 
host, and is further protected during the winter by the host’s puparium. 
(11) The adults of a brood are usually of the same sex. It is believed that the 
occasional mixed broods originate from a fertilized and an unfertilized egg depos¬ 
ited in the same host egg. 
LITERATURE CITED 
(1) Hill, C. C. 
1922. A PRELIMINARY ACCOUNT OF TWO SERPHOID (PROCTOTRYPOID) 
parasites of the hessian fly. Proc. Ent. Soc. Wash. 24: 
109-117. 
(2) - 
1923. platygaster vernalis (myers), an important parasite of the 
hessian fly. Jour. Agr. Research 25: 31-42, illus. 
(3) Leiby, R. W. 
1922. THE polyembryonic development of copidosoma gelechiae, 
with notes on its biology. Jour. Morphology 37: 195-285, 
illus. 
(4) -and Hill, C. C. 
1923. the twinning and monembryonic development of platygaster 
hiemalis, a parasite of the hessian fly. Jour. Agr. Research 
25: 337-350, Ulus. 
(5) Marchal, P. 
1904. RECHERCHES SUE LA BIOLOGIE ET LE DlSVELOPPEMENT DES HYMlSN- 
OPT&RES PARASITE3. I. LA POLYEMBRYONIE OU GERMINOGONIE. 
Arch. Zool. Exp. et Gen. (IV) 2: 257-335, illus. 
( 6 ) - 
1906. RECHERCHES SUR LA BIOLOGIE ET LE DiSVELOPPEMENT DES HYM^N- 
OPT$3RES PARASITES. II. LES PL AT YG ASTERS. Arch. Zool. Exp. et 
Gen. (IV) 4: 485-640, illus. 
(7) SlLVESTRI, F. 
1906. CONTRIBUZIONI ALLA CONOSCENZA BIOLOGICA DEGLI IMENOTTERI 
PARASSITI. I. BIOLOGIA DEL LITOMASTIX TRUNCATELLUS (DALM.) . 
Ann. R. Scuola Sup. Agr. Portici, v. 6, 51 p., illus. 
( 8 ) - 
1916. SULLA MAT UR A ZI ON E DELL ’OVO, FECONDAZIONE E FORMAZIONE DEL 
TROPHAMNIOS NEL PLATYGASTER DRYOMYIAE SILV. (iMENOTTERO 
proctotrtjpide). Atti R. Accad. Lincei, Rend. Cl. Sci. Fis., 
Mat. e Nat. (V) 25 (sem. 2): 121-128, illus. 
<9) - 
1921. CONTRIBUZIONI ALLA CONOSCENZA BIOLOGICA DEGLI IMENOTTERI 
PARASSITI. V. SVILUPPO DEL PLATYGASTER DRYOMYIAE SILV, 
(fam. proctotrupidae). Bol. Lab. Zool. Gen. e Agr. R. Scuola 
Sup. Agr. Portici. 11: 299-326, illus. 
