14 Contagious Diseases of the Chinch-bug. 
t 
The following observations made by Mr. Barber on the color 
changes of chinch-bugs will be of interest here : 
August 19. Chinch-bugs in a millet field near the University 
were seen to be piling up especially about bases of tufts of millet 
or grass. Bugs seem to be mostly brown and black, with some 
pink ones. These proved to be those which had newly moulted 
from the larval to the pupal stage and had not yet turned black. 
Morning cloudy and cool, rainy later in forenoon. Pink or 
flesh-colored bugs, the pupe freshly moulted from larval stage, 
were taken to the laboratory and put into test tubes in several lots. 
In one tube only those which were moulting or had scarcely 
scarcely finished were used. Bugs put in from 12 mM. tol P. M. 
At 3:30 Pp. M. all lots had changed to a black color. Two lots 
which had been kept in a dark place'during all this time were 
also black. Later experiments with a bug which was put in a 
tube just at its moulting time shows that the change in color 
may occur in two hours or less. Some larve were put into a 
dark closet on afternoon of August 19. August 20 in the morn- 
ing several were found to have moulted and the pup were black 
as those kept in the light. So it appears that the coloration 
takes place in darkness as well asin daylight. One pink bug 
was killed with ether on afternoon of August 19, and color was 
found unchanged, 7. e., still pink on morning of 20th. It is evi- 
dent that in this field at least there was a characteristic bunch- 
ing and moulting stage preceding the black pupa stage. Moults, 
or what appeared very much like them, were found very much 
earlier in rolled-up leaves of millet where only young red bugs 
were present. Eggs were found in the same places. 
August 20. A bug was put into a test tube when: moulting 
from larval stage. 
9:07 a4.m.—Pink bug, partly out of brown skin. 
10:07 4. m.—Bug much darker in color. 
10:50 a. m.—Bug black. 
September 16. A bug in the pupal stage, just moulting to the 
adult stage, at 11 A.M. was put intoavial. At 12:55 p.w., the 
black spots on the wings were as distinct as in old adults, and 
the body was becoming brownish. At 2 p.m. the body was 
deeper brown. At 8 A.M. of the following day the bug had the 
characteristic of the old adults. 
