INSECT ENEMIES AND THEIR CONTROL 117 
The two sexes of the nematode are shown in Figs. 35 
and 36. These worms are so minute that it is necessary 
to use enlarged illustrations in order to show their 
various features. Fig. 35 represents the mature female, 
which is nearly pear-shaped and less than a millimeter in 
length. The body cavity of the female is occupied by 
eggs and larve. Fig. 36 shows the slender, threadlike 
male, which is 1 to 1.5 millimeters in length, with en- 
larged parts. Scofield, of the U. S. Department of Agri- 
culture, gives the following life history of the nematode 
in Circular 91, U. S. Bureau of Plant Industry: 
“The larve of the gall worm upon hatching from the egg, which 
hatching sometimes occurs within the body of the parent, ultimately 
escape from the host plant and live for a period in the surrounding 
soil. These larve, although very active, have but little power of 
progressive locomotion, and the spread of infection from place to 
place must depend upon the transportation of infested soil or in- 
fested plants. Soon after emerging from the parent and the tissue 
of the host plant these larva seek other roots and bore their way 
into the plant tissues by means of a spearlike structure, which is 
protruded from the mouth. They feed upon the cell sap of the host 
plants. 
“After fertilization takes place the females begin reproduction 
by forming eggs within the body. These eggs are laid at the rate 
of from 10 to 15 a day, and it is estimated that one female may lay 
as many as 500 eggs. After completing the egg-laying process the 
female dies, the male having died soon after fertilizing the female. 
“The worm lives from one season to the next, either in the egg 
stage or in the larval stage within the host plant. The life of the 
individual worm is short (only a few weeks), when temperature 
and moisture conditions are such as to favor growth.* It is pos- 
sible, therefore, to greatly reduce the numbers, if not to exterminate 
the worm entirely, by keeping the infested land free from plants 
upon which the worm can feed.” 
The characteristic root galls of the cucumber, pro- 
duced by this parasite are shown in Fig. 37, of the 
* Additional information concerning the life history of this Parasite, with 
a list of susceptible plants and details of experiments in controlling the nematode 
in the southeastern United States, may be found in Bulletin 217 of the Bureau of 
Plant Industry, entitled ‘“Root-Knot and Its Contrgl,’ by Dr. Ernest A. Bessey. 
