THE COEN ROOT-WORM. 
(.Diabrotica longicornis , Say.) 
Order Coleoptera. Family CHRYsoMELTDiE. 
j [Plate Y, Figs. 1—5.1 
4 
[n an elaborate account of this species published in my first 
nual report, I remarked that it was not yet known whether this 
ect would be found injurious to broom-corn or sorghum. In my visits 
sorghum fields in Champaign, in July, I found it sparingly in 
reral fields which had been planted to sorghum for two or more 
irs in succession, working upon the roots of these plants in a 
inner precisely similar to that in which it attacks the corn. 
1 
It did not occur here, however, in sufficient numbers to threaten 
•ious injury to these crops, being, for example, less numerous in 
•ghum fields than in fields of corn adjacent which had been 
>pped for a longer time without rotation. 
rhe only practical conclusion which it is at present necessary to 
iw is this: When a field of corn has been badly infested by this 
3t it will not be prudent to plant sorghum there the following 
ir,* since the young worms hatching from the eggs in spring might 
uly make a most destructive attack upon the sorghum plants. 
[ append here a summary account of this insect extracted from 
3 article in my last report, already referred to: 
“The corn root-worm, in the form in which it affects the roots of 
m, is a slender white grub, not thicker than a pin, from one- 
lrth to three-eighths of an inch in length, with a small brown 
ad, and six very short legs. It commences its attack in May or 
ne, eating its way beneath the surface, and killing the root as 
’>t as it proceeds. Late in July or early in August it transforms in 
3 ground near the base of the hill, changing into a white pupa, about 
;een hundredths of an inch long and two-thirds that in width, look- 
; somewhat like an adult beetle, but with the wings and wing¬ 
ers rudimentary, and with the legs closely drawn up against the 
iy. A few days later it emerges as a perfect insect, about one- 
h of an inch in length, varying in color from a pale greenish- 
)wn to bright grass-green, and usually without spots or markings 
any kind. The beetles climb up the stalk, living on fallen pollen 
