REPORT OF THE COMMITTEE ON DISEASE. 
615 
live over winter before laying- its eggs, it contains no worn- 
out adults.” 
Extract from Special Bulletin, May 7, 1895 : 
“ The white fungus causing insect disease takes effect on 
the weakened insect more readily than on one in full vigor, 
on the full grown chinch bug than on the young; and hence, 
most easily of all, on spent adults which have already laid 
their eggs and are about to perish by the natural termination 
of their life period. 
“ The white muscardine is a native disease of the chinch 
bug, and a large number of other insects as well. It never 
dies out entirely, but is likely to appear spontaneously over a 
large extent of country when conditions favorable to its de¬ 
velopment are long maintained. 
“ Two generations of the chinch bug appear every year, 
and when each of these generations matures the adult bugs 
commonly take wing and scatter, thus disappearing from 
fields, or parts of fields, heavily infested by them. Such dis¬ 
persal has often been mistaken for a destruction of chinch 
bugs by disease. One generation matures shortly after wheat 
harvest and the other in late summer and in the fall. The 
chinch bug sheds its skin four times while growing, and the 
empty skins left by it are often mistaken for dead bugs ; a 
mistake which has often led to a false conclusion as to the 
effect of these infection experiments. The cast skins never 
bear wings as the insect does not moult after its wings are 
formed. They may further be readily distinguished from the 
dead bugs by the fact that when pressed between the thumb 
nails they are readily seen to be empty shells.” 
The following is an extract from a letter of May 27th, 
1895, from Prof. Forbes : 
“You will doubtless be interested to know that recent 
visits through the wheat fields of the worst infested parts of 
southern and western Illinois show that the chinch bug dis¬ 
ease is abundantly present in these fields, multitudes of the 
old bugs having died with it among wheat roots, where the 
young, as they hatch, will be exposed to immediate infection. 
Its rapid propagation among the new generation consequently 
depends almost wholly on the weather.” 
