116 
parasite are deposited inside the boll worm eggs hj the female, which 
is provided with a sharp ovipositor capable of piercing the hard chiti- 
nous shell of the egg. The young parasitic grubs eat out the contents 
of the egg^ thus preventing hatching. 
The following tables, compiled from a large number of records, show 
verv graphically the large percentage of eggs which fail to hatch on 
account of these parasites: 
Table XLY. — rercentages of jnrras-itized eggs on corn, 1903. ' 
Date of exami- 
nation. 
Number 
of eggs 
ex- 
amined. 
Locality. 
Eggs on— 
Per cent 
para- 
sitized. 
Mavol 
194 
100 
144 
283 
747 
100 
Victoria, Tex. 
do... 
do 
do 
do 
Calvert, Tex 
Corn silks 
84 
"TO 
Do 
Corn silks 
Corn leaves 
do 
do 
83 
June 3 
70 
Do 
44.8 
Augusts 
S 
Table XLVI. — Percentages of eggs parasitized, 1904. 
, Number 
Date of exami- I of eggf' 
nation. I ex- 
amined. 
Locality. 
Per cent 
para- 
sitized. 
May 16 
June 3 
June 10 
August 1 
August 12 
Do 
Do 
August 14 
August 16 
August 20 
Do 
August 29 
September 3 
September 7 
September 24 - - . 
October 19 
150 
10 '. 
20 . 
40 . 
31 j. 
32 I. 
10 '. 
40 |, 
40 
40 I 
40 I 
40 : 
34 
44 ' 
40 ■ 
28 
Paris, Tex. 
....do 
...-do 
.--.do.-... 
.-..do--... 
.---do 
-..-do 
--..do 
-...do 
...-do 
--..do 
--.-do 
.--.do 
.-.-do 
...-do 
....do 
Corn. 
do 
do 
do 
Corn silks 
Corn leaves 
Tobacco leaves 
Corn leaves . . . 
Cotton 
Corn leaves . . . 
Corn silks 
Corn leaves . . . 
Cotton 
Tomato leaves. 
Corn leaves . . . 
do 
59.3 
70 
80 
50 • 
30 
100 
22.5 
92.5 
62.5 
75 
35.5 
86.5 
82.5 
43 
Observed average parasitized during 1903. 
Observed average parasitized during 1904. 
General average, all observations 
Per cent. 
.... 63.3 
.... 63.4 
.... 63.35 
Glancing down the table, it will be noted that the maximum parasi- 
tization is on corn leaves, with corn silks next in susceptibility, and 
parts of the cotton plant considerably in the rear. This may pos- 
sibly be due to the hindrance oii'ered to the locomotion of the Tricho- 
gramma during the process of oviposition by plant hairs, since the 
leaves of corn are more nearly free from these than the other objects 
mentioned. 
The first appearance of Trichogramma in the spring corresponds 
approximately with the first general occurrence of boll worm eggs on 
