JOURNAL OF AGRICULTURAL RESEARCH 
DEPARTMENT OP AGRICULTURE 
Voiy. V Washington, D. C., December 20, 1915 No. 12 
BIOLOGY OP APANTELES MILITARIS 
By Daniee G. Tower, 1 
Scientific A$sistant> Cereal and Forage Insect Investigations , 
Bureau of Entomology 
INTRODUCTION 
The results herewith presented deal with Apanteles mUitaris Walsh, 
a braconid endoparasite of the army worm (Heliophila unipuncta Haw.). 
The series of experiments on which the main part of this paper is based 
was begun on September 29, 1914, at La Fayette, Ind. They were 
carried on in the laboratory, the parasitized caterpillars being kept in glass 
vials plugged with cotton and fed fresh corn leaves as required. The 
laboratory windows were left open, so as to make conditions as nearly 
like those outside as possible. During the few cold days which were 
experienced the laboratory was heated to the normal room temperature. 
During the first two weeks in August additional records were kept of 
the time spent in the cocoon by the parasites, and in these experiments 
cocoons were kept in tin salve boxes in an outdoor insectary. On 
November 16 a series of experiments was started indoors to determine 
whether or not this species is parthenogenetic, and conclusive results 
were obtained. The caterpillars used in the experiments were raised 
from eggs unless otherwise stated. 
DESCRIPTION OF LIFE STAGES 
THE EGG 
The egg measures 0.09 to 0.10 mm. in length and 0.025 to 0.028 mm. 
in width. It is rounded at one end, more or less pointed at the other, 
and slightly curved, the rounded end bearing a distinct micropyle. 
Subsequent swelling of the egg during the growth of the embryo causes 
1 The writer wishes to acknowledge his indebtedness to Messrs. J. J. Davis and A. F. Satterthwait, of the 
Cereal and Forage Insect Field Station of the Bureau of Entomology at Ea Fayette, Ind., for many 
helpful suggestions and material, and to Messrs. J. A. Hyslop and G. G. Ainslie, of the Bureau of Ento¬ 
mology, for their interest and kindness in collecting material and data for him at their respective stations. 
He is also indebted to Messrs. A. B. Gahan and W. R. Walton, of the Bureau of Entomology, for the 
determination of specimens and for the drawings of the three larval stages, respectively. 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
bj 
Vol. V, No. 13 
Dec. 20,1915 
K —21 
