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form only a nubbin. ‘The injured plant also matures slowly, remain- 
ing green longer than the average, and being thus especially subject to 
injury by frost. 
A closer examination of the young plant will commonly show a 
perforation of the underground part of the stem either at or near the 
upper circle of roots. Later, as the corn plant increases in size, the 
roots themselves are seen to be gnawed irregularly, great holes or 
notches being eaten out, first in one direction and then in another, until 
the roots are severed or consumed. In the larger roots the larva may 
perhaps completely bury itself, but it is much more likely to eat in and 
out irregularly than is the smaller northern corn root worm presently 
to be described. It differs from this last species likewise in the fact that 
it commonly devours everything as it goes, leaving little or no refuse 
in its burrows; and in the further fact that it works all along to some 
extent in the base of the stalk, which it penetrates, but not deeply, 
finally causing the stalk to blacken and rot where water gets admis- 
sion to its injuries. Its attack on corn is also earlier, briefer, and much 
more vigorous and destructive, owing to the larger size of the larva and 
its more rapid growth and earlier maturity. Even in’ well-grown corn 
it very commonly bores into the stalk beneath the upper circle of 
brace roots, or behind the sheath of the lower leaf—habits in which 
it differs from the northern corn root worm. 
Search for this root worm should be made in or about the injured 
parts—from the middle of May to the middle of August in the lati- 
tude of the southern half of Illinois. It is a soft, slender-bodied, worm- 
like insect, a little over half an inch in length when full grown, and 
nearly ten times as long as thick. The -surface is slightly wrinkled or 
warty, white when young, and yellowish when old. The head is dark 
brown, sometimes nearly black, and there is a pale brown leathery patch 
on the top of the segment next behind the head, and a nearly circular 
similar patch on the top of the last segment of the body. The legs are 
very short and small, and the skin bears only a few long scattered hairs. 
It seems most likely to attack early planted corn, and hence in the 
Northern States has been found most frequently in sweet corn. An in- 
jury of fifty per cent. is a not unusual effect of its presence in South- 
ern Illinois, and elsewhere it has been reported as sometimes destroy- 
ing almost every hill when the corn was young. 
This corn root worm has not been taken in the act of injury to the 
roots of any other plant than corn, but has once been seen eating off 
a stem of young wheat in fall.* Lugger found the pups among the 
roots of a common prairie plant, the cone flower (Rudbeckia), but says 
nothing of injury to that plant; and my assistant, Mr. Marten, re- 
ports the occurrence of young larve among the roots “of Cyperus strigo- 
sus and Scirpus fluviatilis—two sedges common in moist low lands, the 
roots of which presented the same appearance of injury as those of in- 
fested corn 
The food of the adult Diabrotica 12-punctata is widely varied, ap- 
parently much more so than that of the northern Diabrotica. It has | 
been for a long time commonly known as a squash beetle, eating both 
* Webster, in Bull. 45 (1892), Ohio Agr. Exper. Station, p. 208. 
