JOINAL OF AGRiaiTDRAL ISEARCH 



DEPARTMENT OF AGRICULTURE 

 Vol. V Washington, D. C, December 20, 1915 No. 12 



BIOLOGY OF APANTELES MILITARIS 



By Daniel G. Tower,' 



Scientific Assistant, Cereal and Forage Insect Investigations, 



Bureau of Entomology 



INTRODUCTION 



The results herewith presented deal with Apanteles militaris 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, 191 4, 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 com 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 e.gg measures 0.09 to o.io 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 &gg during the growth of the embryo causes 



• 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 La 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, Vol. V, No. is 



Dept. of Agriculture, Washington, D. C. Dec. 20, 1915 



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