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THEHK CORN ROOT-WORM. 
(Diabrotica longicornis, Say.) 
Order Contnoptera. Family CHrysomenipa. 
[Plate V, Figs. 1—5.] 
In an elaborate account of this species published in my first 
annual report, I remarked that it was not yet known whether this 
insect would be found injurious to broom-corn or sorghum. In my visits 
to sorghum fields in Champaign, in July, I found it sparingly in 
several fields which had been planted to sorghum for two or more 
years in succession, working upon the roots of these plants in a 
manner precisely similar to that in which it attacks the corn. 
It did not occur here, however, in sufficient numbers to threaten 
serious injury to these crops, being, for example, less numerous in 
sorghum fields than in fields of corn adjacent which had been 
cropped for a longer time without rotation. 
The only practical conclusion which it is at present necessary to 
draw is this: When a field of corn has been badly infested by this 
pest it will not be prudent to plant sorghum there the following 
year, since the young worms hatching from the eggs in spring might 
easily make a most destructive attack upon the sorghum plants. 
I append here a summary account of this insect extracted from 
the article in my last report, already referred to: 
“The corn root-worm, in the form in which it affects the roots of 
corn, is a slender white grub, not thicker than a pin, from one- 
fourth to three-eighths of an inch in length, with a small brown 
head, and six very short legs. It commences its attack in May or 
June, eating its way beneath the surface, and killing the root as 
fast as it proceeds. Late in July or early in August it transforms in 
the ground near the base of the hill, changing into a white pupa, about 
fifteen hundredths of an inch long and two-thirds that in width, look- 
ing somewhat like an adult beetle, but with the wings and wing- 
covers rudimentary, and with the legs closely drawn up against the 
body. A few days later it emerges as a perfect insect, about one- 
fifth of an inch in length, varying in color from a pale greenish- 
brown to bright grass-green, and usually without spots or markings 
of any kind. The beetles climb up the stalk, living on fallen pollen 
