Table XXIX. 
79 
-Percentage of infestation of corn plants at different localities in the 
cotton belt. 
Locality. 
Date of 
exami- 
nation. 
Age of 
corn. 
ai 
o 
3 
3 
It 
op 
Locality. 
Date of 
exami- 
nation. 
3 
1 
<v 
Time 
of 
plant- 
ing. 
Calvert, Tex 
Comanche, Tex... 
Do 
June 27 
July 22 
July 27 
July 26 
June 25 
May 29 
July 26 
July 25 
May 15 
July 20 
Aug. 4 
July 16 
June 27 
July 30 
Aug. 9 
June 29 
July 15 
June 30 
Ear's!. 
Ripe.. 
Ears . . 
...do.. 
...do.. 
...do.. 
...do.. 
...do.. 
80 
500 
500 
500 
168 
60 
500 
500 
60 
20 
150 
42 
790 
47 
58 
790 
54 
500 
470 
484 
102 
58 
484 
67 
100 
94 
97 
60 
96 
97 
80 
70 
80 
91 
- 99 
68 
80 
100 
70 
96 
95 
Elm Grove, La 
Do 
June 24 
July 17 
do ... 
50 
78 
62 
87 
100 
80 
90 
90 
100 
75 
80 
100 
60 
100 
65 
95 
90 
100 
Shreveport, La 
Cooper, Tex 
PnrsiPflnn Tex 
Montgomery, Ala. 
Do 
Sept. 12 
do 
Early. 
I^ate 
Dallas, Tex 
Gilmer, Tex 
Groesbeck, Tex . . . 
Hempstead, Tex.. 
Albany, Ga 
Do -'.. 
Sept. 7 
do . 
Early. 
Late. 
Augusta, Ga 
Do 
Memphis, Tenn... 
Birmingham, Ala. 
Do 
Sept. 10 
do ... 
Sept. 15 
Sept. 10 
do ... 
Early. 
66 
42 
Late. 
Early. 
Mineola, Tex 
Morgan, Tex 
Navasota,Tex 
Quinlan, Tex 
Do 
...do .. 
...do.. 
...do.. 
...do.. 
...do.. 
...do.. 
...do.. 
...do.. 
404 
125 
60 
100 
40 
245 
75 
80 
"'74' 
80 
'iss' 
52 
69 
137 
370 
124 
41 
80 
40 
173 
72 
76 
Do. 
Late. 
Lake City, Fla .... 
Lakeland, Fla 
Archer, Fla 
Do . : 
Sept. 14 
Sept. 7 
Sept. 6 
do . 
Early. 
Do. 
Do. 
Rosenberg, Tex... 
Do 
Late. 
Batesburg, S. C . . . 
Do 
Sept. 10 
do ... 
Early. 
Late. 
The progress of infestation during the season is shown by the next 
table, which gives results of counts made during season of 1904 on 
two fields near Paris, Tex. 
Tabi;E XXX. — Progress of infestation during season. 
Date of 
exami- 
nation. 
Age of corn. 
Per cent of 
infestation. 
Date of 
exami- 
nation. 
Age of corn. 
Per cent of 
infestation. 
May 31 
June 16 
3 to 4 feet high 
5.4 
27.0 
56.0 
May 31 
July 21 
3 to 5 feet high 
1.4 
Silk and tassel 
Roasting ears 
97.2 
July 20 
CANNIBALISM. 
The difference in mortality on corn and cotton is mainly due to the 
cannibalistic habits of the larvae themselves. When young, this habit 
does not manifest itself very strongly unless the bollworms are 
pressed for food, but after they are half -grown or larger they become 
extremel}^ vicious and attack one another on the slightest provocation. 
If two larvpe are feeding in one ear of corn and their paths acciden- 
tally cross, they become irritated at once and snap at each other with 
the mandibles. Usually the larger one is victor and makes a meal of 
the smaller. If, as is sometime the case, both are of approximately 
the same size, it is not unusual for both to be so injured as to die. 
Even two larvse peaceably crawling about will almost always fight if 
they come together unexpectedly. They do not evince any desire to 
hunt out their fellows, however, and it appears to be merely chance 
which brings them into contact. Observers have often been inclined 
to think that cannibalism was induced by external annoyances caused 
22051— No. 50—05 6 
