94° 
Journal of Agricultural Research voi. xxvn, no. 12 
The eggs are elongate, cylindrical bodies with the length about twice 
the diameter and granular in appearance. They vary somewhat in size, 
averaging about 40 by 85 ju. They have a single nucleus and a smooth 
tough chitinlike coat. The larvae emerge from the eggs a few days after 
these have been deposited, being quite fully developed while still in the 
uterus of the female. The freshly hatched larvae are about 500 /jl in 
length, threadlike in appearance, and unable to withstand unfavorable 
conditions. 
This so-called first stage is of short duration, and after one or more 
molts the larvae reach the second stage of their development. They 
remain in this stage until after they have escaped from the gall, have 
entered the tissues of another host plant, and have caused the formation 
of other galls. They vary in length from about 700 to 900 ix and in 
width from 15 to 20 /x, or about one-fortieth of their length. Their 
structure is very simple, consisting of a tube within a tube, the outer 
one being the body covering and the inner one the digestive tract. 
The anterior end is provided with a hollow buccal spear with which the 
organism probably pierces plant tissues and extracts nourishment after it 
has escaped from the gall and entered another plant. There is no 
sexual differentiation in this stage, but the beginning of the reproductive 
system appears as a half-moon-shaped, light area located midway be¬ 
tween the ends of the intestine. 
Investigators generally agree that the larvae take practically no 
nourishment until after they have invaded the tissues of the host plant. 
This belief seems to be borne out by the fact that as the free-living stage 
is prolonged the larvae become more transparent. The translucent 
granular matter in the intestine which is regarded as reserve food grad¬ 
ually disappears. Yet it seems reasonable to suppose that in order to 
produce such pronounced deformities in the plant before heading has 
begun the organism must use its buccal spear and esophageal bulb to 
puncture the cells and extract plant juices while still in the free-living 
stage. 
After entering the host tissues the larvae rapidly develop into mature 
male and female adults. These are large enough to be clearly visible 
to the naked eye. The females average about 4 mm. and the males about 
2.5 mm. in length. Both are proportionately wider than the larvae. 
The reproductive system in each is fully developed and occupies most 
of the body space, especially in the female. Egg layihg continues for 
some weeks, each female being capable of depositing as many as 2,000 
or more eggs during that period. 5 
The number of mature nematodes, as well as the relative number of 
males and females, varies widely in different galls. Green galls from 
spelt, wheat, and emmer were opened and the mature nematodes care¬ 
fully counted. The results are shown in Table XII. 
• For a technical description of eggs, larvae, and adults, see Department Bulletin 842 05). 
