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UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1336 
Washington, D. C. T September, 1925 
BIOLOGICAL STUDIES OF THE GREEN CLOVER WORM 
By Chas. C. Hill, Assistant Entomologist, Cereal and Forage Insect Jhvestiga- 
tions, Bureau of Entomology 9^ , . . ^ ai 
CONTENTS 
mmm 
Introduction 1 
Systematic history 1 
Synonymy 2 
Geographical distribution 2 
Food plants - 2 
Page Vsffeito^ Page 
Description of stage^i^^3j^wlT_A - '^ 
Life history and habits . '* - .-. 8 
Seasonal history 14 
Natural enemies 16 
Literat ure cited 19 
INTRODUCTION » 
The green clover worm, Plathypena scabra Fabr., has long been 
recognized as a pest of wide distribution and injurious to various 
crops. In 1914 and 1915 it occurred in abundance in alfalfa fields 
in the vicinity of Nashville, Tenn., and studies on its life history 
were commenced by the writer at that time. During the summer of 
1919 a general outbreak of this pest on different crops occurred of 
sufficient severity to attract the attention of agriculturists through- 
out a large portion of the East. A popular account with recom- 
mendations for control as an alfalfa pest, based on studies conducted 
by the writer in Tennessee, was published (5) 2 in 1918. The present 
bulletin embodies technical details regarding the biology of this insect 
which necessarily were omitted in the popular account. 
SYSTEMATIC HISTORY 
Owing to sexual dimorphism in this species, the sexes were origi- 
nally considered as distinct species, a mistake which was not dis- 
covered until 1873, when Lintner (7), through study of Ins own col- 
lection and those of others, found that the species, then known as 
Hypena scabra Fabr. and Hypena erectalis Guen., were each repre- 
sented in collections by a single sex. He communicated this obser- 
vation to Grote, who substantiated it by further examinations; and 
later in the year both men published the fact that erectalis Guenee 
was merely the female form of scabra Fabricius, of which heretofore 
only the male form had been known. Grote (J), in his paper, erected 
for the species the genus Plathypena. 
1 The author expi esses his appreciation of helpful suggestions, received from Geo. G. Ainslie, under whose 
direction work on this insect was first started at Nashville, Tenn., and to Carl Heinrich for guidance in 
the construction of pupal and setal charts. 
- Reference is made by number (italics') to " Literature cited." p. It*. 
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