125 
The appearance of a larva after the disease is well advanced is char- 
acteristic. The body loses its firm consistency and becomes quite 
flabby, while its color fades to a rather uniform greenish yellow. (See 
PI. XIX, fig. 3.) The larva loses the power of coordinated move- 
ment, only wriggling or twitching spasmodically when disturbed, and 
soon beofins to turn darker. Within a few hours after its death it 
assumes a purplish black color, and the whole internal contents liquefy 
more or less completely. When the skin is broken this liquid mass is 
seen to have a distinct reddish tinge. 
Larvae living in a humid atmosphere seem to be more susceptible to 
the disease. The following table, containing some of the more com- 
plete records made during the course of the work, will give a general 
idea as to the percentage of larvae destroyed b}^ this disease: 
Table L. — Percentage oflarvx destroyed by bacterial disease. 
Date of col- 
lection. 
Locality. 
Food plant. 
Number 
collected. 
Per cent 
diseased. 
July 1, 1903 
Aug. 3,1903 
Aug. 4,1903 
Aug. 17,1903 
May 28,1904 
Aug. 20,1904 
Aug. 2p,1904 
Aug. 30,1904 
Sept. 24, 1904 
Oct 7 1904 
Victoria Tex 
Corn 
2-3 
Calvert, Tex 
do 
300 
U 
.do . . 
do 
6 
do 
Alfalfa 
Corn 
81 
56 
184 
40 
12 
111 
17 
37 
10 
Dallas, Tex 
10 
Paris Tex . 
Cotton 
do 
49 
do 
5 
do 
Corn 
17 
..do 
.do 
63 
do 
Alfalfa 
do 
12 
Oct. 24,1904 
do 
29 
Averages: Corn, 18 per cent; cotton, 27 per cent; alfalfa, 17 per cent. 
The great discrepancies in the difi'erent lots are in large part due to 
the fact that some counts were made by examining larvae freshly col- 
lected, and others from larvae kept in the laboratory for a considerable 
time, a few dying each day. The large percentages indicated in some 
of the columns, however, show plainly that under certain conditions a 
great proportion may succumb to this malady. One unfortunate cir- 
cumstance is the fact that it is nearly always the larger larvae which 
are attacked. 
In the laboratory several cultures were made from a dried larva that 
had died from bacterial disease. After five days all the cultures had 
acquired a pinkish tinge, and each, when examined under the micro- 
scope, yielded a ciliated organism of a bright crimson color, readily 
visible with a one-twelfth-inch oil-immersion lens, without staining. 
Four health}^ worms were infected from the cultures by pressing the 
head and mouth parts against the red gelatine. Of the larvae thus 
infected, two died within two days with the symptoms of the bacterial 
disease; one escaped, and the fourth, full-grown when infected, 
pupated successfull3^ From one of the first cultures, two more were 
then started and after six days were characteristically red. These 
