LEPIDOPTERA 



237 



is an important insect 

 insect (Fig. 414) is a 



The cotton-worm Alabama argillacea. — This 

 pest in the cotton-growing states. The adult 

 brownish moth with its fore wings crossed with 

 wavy lines of darker color and marked with a 

 bluish discal spot and two white dots as shown 

 in the figure. This moth is found in the northern 

 states and even in Canada in the latter part of 

 the summer and in the autumn. But this oc- 

 currence in the North is due to migrations from 

 the South, as the insect can not survive the 

 winter north of the tropics. The larva feeds on 

 the foliage of cotton ; and as there are five or six generations in a year, the 

 multiplication of individuals is very rapid, and the injury to the cotton great. 



Fig. 414. — Alabama argillacea. 



The Plusias 



There are nearly seventy species of moths in this group of which most 

 of the typical members were formerly placed in the genus Plusia. 



In a large number of these the fore wings are marked with metallic- 

 colored scales. The most common form of this marking is a silvery spot, 

 shaped something like a 



comma, near the center o 



of the wing (Fig. 415). 

 In some of the species 

 the metallic markings 

 cover a large portion of 

 the fore wings, in others 

 they are wanting. 



a 



Fig. 415. — Aulographa falcifera. 



The larvse have only 

 three pairs of prolegs, 

 the first two pairs being 

 wanting; due to this 

 fact they walk with a 

 looping motion (Fig. 

 416) resembling some- 

 what that of the geometrids. 



The two following species have attracted attention by their injuries 

 to cultivated plants; the celery looper, Autographa falcifera, and the 

 cabbage looper, Autographa brassier. 



FlG. 416. — The cabbage-looper, Autographa brassica: a, 

 male moth; b, egg; c, full-grown larva; d, pupa in cocoon. 

 (After Howard and Chittenden.) 



The Catocalas 



There are many species in North America of these handsome moths 

 but as a rule their caterpillars are not of much economic importance. m 



Lj I L I ■ R A R Y 



