UNITED STATES DEPARTMENT OF AGRICULTURE 
$UI BULLETIN No. 1016 
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Contribution from the Bureau of Entomology 
L. O. HOWARD, Chief 
Washington, D. C. 
PROFESSIONAL PAPER 
January 31, 1922 
BIONOMICS OF THE CHINCH BUG. 
By Philip Luginbill, Entomological Assistant, Cereal and Forage Insect 
Investigations. 
CONTENTS. 
Page. 
Introduction 1 
Seasonal history in South Carolina — 2 
Behavior 3 
Mating 3 
Life history of the chinch bug 4 
Page. 
Description of the egg and nymphal 
instars 10 
Sexual differences among adults 10 
A parasite of the adult 11 
INTRODUCTION. 
During several years past the biology of the chinch bug (Blissus 
leucojiterus Say) has been studied in South Carolina with a view to 
the control of the insect in that region. It is a pest of considerable 
importance, especially in some of the northern counties of the State. 
Many planters in this region will plant no grain, giving as a reason 
that attempts to grow grain result in producing chinch bugs, and as 
a consequence they are unable to make a corn crop. Coincident with 
the conduct of field investigations, some time was devoted to a study 
of the insect in the laboratory at Columbia, and although this work 
is not complete, certain novel facts regarding the life history of the 
pest have been learned which make it advisable to publish imme- 
diately the information thus obtained. Wherever the chinch bug has 
been treated in the literature, it has always been represented as pass- 
ing through five instars in its development. By means of the experi- 
ments conducted at Columbia^ S. C, it has been shown that in this 
locality the insect has six instars, instead of five, exclusive of the egg 
stage, viz, five immature stages, the sixth being the adult stage. The 
figures of the stages of this insect given by C. V. Riley, which have 
been used over and over again in various bulletins and other works 
on this subject, therefore are incorrect, at least in so far as South 
Carolina is concerned. Specimens of the different stages were pre- 
served at Columbia, and from these drawings have been made by 
70208 — 22 Bull. 1016 
