24 
distance. In Hancock county, in Western Illinois, late in June, not over 
two or three per cent. of the heads were blighted m the fields worst 
infested, and a still smaller ratio were damaged in the rye adjacent. 
In every case the head was destitute of kernels, and its growth 
had often been arrested before it had reached full size. On strip- 
ping down the sheath of the upper leaf, the stalk was always. 
found eroded and withered for a distance of an inch or so above 
the internode, and the stem could, of course, be readily pulled out 
from the enclosing sheath. In Prof. Riley’s notes of the work of 
this brood near St. Louis, Missouri, he remarks:  ‘‘In most fields 
. about one per cent. of the ears were thus affected, but in two fields 
near Hermann from three to four per cent. were injured in this 
manner. Upon examination, I found that the last or ear-bearing 
joint could invariably be pul led out of its sheath with but a slight 
effort, and that it was perfectly yellow and dry, while the lower end 
bore an irregular and gnawed appearance. Upon splitting open the 
first joint of the stalk, a space of about a quarter of an inch was 
found to be completely corroded, so to speak, and filled with excre- 
mentitious matter.’ Prof. Lintner says: ‘Ihe heads were entirely 
destitute of kernels. Within some of the husks the remains of the 
blossoms were discoverable, showing that their development had 
been arrested before the formation of the grain. Upon removing 
the investing sheath, the stem was found to be discolored and 
shrunken, and: quite dry for three or four inches above the joint, 
and near the joint it was so eaten and shriveled as to be utterly 
useless for the purpose of conveying the sap.” 
It will be seen that the injury done by this insect in fall and 
spring, while similar in its effect to that of the Hessian fly, is quite 
different in character. Both insects, indeed, infest the same part of 
the plant at the same season, but the Hessian fly does not gnaw or 
tear the substance of the stalk. It seems to depend rather upon the 
effect of the pressure of its body imbedded within the sheath in 
arresting the flow of sap and causing it to exude from the stem. 
The second attack of the bulb worm is not only made in a dif- 
ferent way, but at a different point from that of the Hessian fly, 
the latter still confining itself to the lower part of the stalk, and 
damaging the wheat, as before, through the irritation caused by the 
presence of the larve within the sheath; while at this time, as 
already related, the bulb worm attacks the plant and destroys the 
stem above the upper joint. 
NATURAL ENEMIES. 
The fact is well known that to the aid of parasites we owe the 
preservation of our wheat crops from continuous injury by the Hes- 
sian fly,—parasites which effect their purpose by piercing the 
bodies of the larve imbedded in the plant, and depositing in each 
a minute egg which afterwards develops a maggot that devours its 
host. The wheat Oscinide of Europe are also kept within bounds 
by a parasite of similar habit, known under the name of Calinius 
niger, and the presumption was consequently very strong that some 
corresponding enemy of our own species would be found. 
