154 
low or green. Metathorax beneath, the distal portion of the 
femora, and the whole of the tibiae and tarsi, black. 
“Head with a basal pit behind antennae. Prothorax above 
smooth and shining, obsoletely punctulate, with a pair of pits, 
one on each side of the middle line. Margin of prothorax sinu¬ 
ate at sides, no prominent angles. Elytra minutely, regularly 
punctulate, each elytron with a humeral prominence. Antennae, 
metathorax beneath, abdomen, and legs, clothed with a fine 
silken pubescence. 
“Length .25-.28 inch; antennae about .19 inch.” 
c. Hoots visibly penetrated and perforated scarcely at all; some¬ 
times decayed at tips , but not eaten away. Principal in¬ 
jury interior , in form of minute burrows which are com¬ 
monly longitudinal. 
THE NORTHERN CORN ROOT WORM. 
(Diabrotica longicornis, Say.) 
(Plate XIV., Fig. 6-8; and Plate XV.) 
The northern or common corn root worm ( Diabrotica longi¬ 
cornis) is by far the most destructive corn root insect depend¬ 
ent on that plant alone. Indeed, it now seems likely that if it 
were not for the fact that it is highly susceptible to a measure 
of prevention which farmers have very generally taken uncon¬ 
sciously, as a part of a sound agricultural routine, it would 
long ago have seriously threatened the profitable continuance 
of corn culture in the very part of the country best adapted to 
that great crop. Even as it is, its injuries are undoubtedly to 
be reckoned by millions of dollars annually*, although the es¬ 
sential facts concerning its ravages and their ready and com¬ 
plete prevention were officially and widely published nine years 
agof. 
INJURIES TO CORN. 
The presence of this insect first betrays itself in badly infested 
fields when the plant is a foot or so high. If at this time patches 
of corn are observed which seem to be standing still, so that 
the plants adjacent leave them behind, giving the field an uneven 
appearance, it is possible—especially if the field has been in corn 
two years or more preceding—that this retardation of growth 
is due to the presence of this corn root worm. In this case, if 
. * Webster estimates the damage to corn in twenty-four counties of Indiana in 1885 at two 
million dollars, basing this judgment on a loss of $16,000 by one large farmer, and on his 
personal knowledge of its distribution and abundance in that State. 
tTwelfth Rep. State Ent. Ill., pp. 29 30. 
