﻿BULLETIN" 8, U. S. DEPARTMENT OP AGRICULTURE. 



Fig. 3. — The western corn 

 rootworm : Egg. High- 

 ly magnified. (Origi- 

 nal.) 



They are deposited mostly in late August and in September, in shallow 

 crevices in the ground, more often among the brace roots of the corn. 

 These eggs hatch the following May and June, and the larvae, always 

 nearly white in color, attack the roots of the corn and never burrow 

 into the lower stem as does the southern bud worm. (See fig. 5.) 

 After completing their growth the larva? abandon the corn roots and 

 construct earthen cells in the soil, within which they change to pupa? 

 (fig. 1), which are white like the larva?, and then, during late July 

 and August, to adults or beetles. There is therefore only one genera- 

 tion annually. The beetles may perhaps live 

 over winter in extreme southern Texas, but 

 they do not do so farther north, where they 

 are of the greatest economic importance. 



DISTRIBUTION. 



The species occurs from Nova Scotia south- 

 ward to Alabama and Mexico, westward to 

 southern Minnesota and South Dakota, and 

 thence south to southern New Mexico. 

 Curious enough, but a matter of decided economic importance, 

 is the fact that its area of destructive abundance does not include 

 all of the territory which it inhabits. The greatest destruction has 

 been wrought, so far as known, in Illinois, Indiana, Ohio, Iowa, Mis- 

 souri, South Dakota, Nebraska, Tennessee, and prob- 

 ably Kentucky. 



HISTORY OF THE INSECT AND ITS RAVAGES. 



The beetle was described in 1823 by Mr. Thomas 

 Say, from specimens taken by him while connected 

 with the Maj. Long expedition to the Rocky Moun- 

 tains, and its habitat was given by him as the Arkansas 

 Territory. 1 



No facts concerning the habits of this insect were 

 recorded until the year 18G6, when specimens of the 

 beetles were referred to Mr. B. D. Walsh by Prof. 

 W. S. Robertson, of Kansas, who found them in 

 large numbers on imphee or sorghum, their natural home being 

 a large thistle. Mr. Walsh, in acknowledging the receipt of the 

 specimens, stated that he had taken three specimens many years 

 before on flowers in central Illinois. 2 Eight years later, in August, 

 1874, Mr. H. Webber, of Kirkwood, Mo., sent some larva? and pupa? 

 to Prof. Riley, with the complaint that the former were burrowing 

 into the roots of his corn and doing considerable damage. In July, 



1 Jourri. Ac:id. Nat. Sci. Phila., vol. 3, p. 460, 1823. 



2 Practical Entomologist, vol. 2, p. 10, 1866. 



Fig. 4. — The west- 

 ern corn root- 

 worm : Pupa. 

 Much enlarged. 

 (Original.) 



