1B 
spread knowledge of this insect, both to the farmer and to the stu- 
dent of the general system of organic nature, will no doubt justify 
an elaborate treatment of it in this report; and I will therefore give 
an account of it as nearly complete as is now possible, presenting 
not only the conclusions reached, but also all the evidence on which 
they rest, so that the intelligent reader may judge of their sound- 
ness for himself. 
a 
Although two papers on this insect have already been published 
in the ninth and tenth reports of this office, the information on 
which they were based was confessedly incomplete, and some of the 
theories there hesitatingly ventured have since proven incorrect; 
and it therefore seems best to treat the whole subject independently. 
‘I have thought it necessary to give with special fullness the partic- 
ulars relating to the amount of the injury, the number of broods, 
and the mode of hibernation, since it is upon these points that pre- 
vious reports have proven to be especially at fault. 
EXTENT AND AMOUNT OF ITS INJURIES. 
The first published mention which has come to my notice of the 
occurrence of this species as an injurious insect, is in the report of 
the Commissioner of Agriculture for 1878, on the 208th page of 
which Prof. C. V. Riley, entomologist to the department, remarks: 
“Myr. Gustavus Pauls, of Kureka, Mo., had his corn seriously dam- 
aged at the roots by the larva of a little beetle (Diabrotica longi- 
corns, Say.,) that was not before known to have any such habits.” 
Prof. Riley was, therefore, not onlythe first to note the injury, but also 
the first to determine the species to which it wasdue. Later, referring 
to this item in the American Entomologist for October, 1880, Mr. Riley 
says: ‘The injuries of this insect to corn roots have, for some time, 
been known to us. * i * We first received it in the larva 
and pupa states in August, 1874, from Mr. H. Weber, of Kirkwood, 
Mo., who found it burrowing in the roots of his corn, and doing 
considerable damage. While the general resemblance to the known 
larve of Diabrotica vittata (the Striped Cucumber-beetle) showed its 
relationship, and we suspected it to belong to D. longicornis, on ac- 
count of the frequency with which this pretty, greenish species was 
found in corn-fields, yet we failed to get positive proof by breeding 
until August 14, 1878, when the first beetle was obtained from larve 
received the previous month from Mr. G. Pauls, of Eureka, Mo.” 
In the Western Rural for May, i279, a correspondent in Warren 
county, Ill., says: ‘‘During the last few years our corn-fields in this 
section have been infested by a small white worm or larva, of which 
farmers generally know but little. Except in size} color and habits, 
it resembles the yellow wire-worm. Instead of disturbing the kernels 
of corn they attack the root, and as soon as corn is up, we find the 
roots dying, and the inside of them filled with these little pests. 
They enter the root at the base of the stalk, and burrow under the 
bark of the root until it is destroyed. They are at first very small, 
and can scarcely be detected with the natural eye, but later they 
appear to be one-half inch in length, with seemingly all appearances 
of the wire-worm in shape.” 
