832 
ANNUAL REPORT OF NEW YORK 
JOINT-WORM FLY. THE DISEASED STRAW. 
worm, and requested the}" should be handed to some naturalist 
for a more exact description and any additional information 
respecting it which could be given. These specimens were for- 
warded to me, and the result of my examination accompanies 
Mr. Rives’ communication. He states that some of his acquaint¬ 
ances had in glass jars hatched the perfect insects from these 
worms, and represent it to be “ a dark-colored gnat, with small 
wings, some want of activity, and little power of flight.” I 
described the diseased wheat and the worm therein, as follows: 
The wheat stalk immediately above the lower joint, is obvi¬ 
ously diseased for a distance exceeding a half inch. It is swol¬ 
len to a size a third larger than it is above or below; it is 
changed to a harder and more wood-like texture; the veins are 
distorted and crowded out of their natural straight and parallel 
direction; and several long spots of a paler color and slightly 
elevated, like blisters, appear. On carefully cutting into these 
blister-like elevations, a hollow cavity is found, which is nearly 
a quarter of an inch long, and tapering to a point at each end. 
In each of these cavities lies a footless worm or maggot, which is 
about ten-hundredths of an inch long (0.10) by four-hundredths 
broad (0.04); of an oval form, rather more tapering towards ono 
end, and divided by slight constrictions into thirteen segments. 
The worm is soft, shining, of a uniform milk-white color, and on 
its anterior end is a small V-shaped brown line, marking the 
situation of its mouth. So exactly does this worm in its form 
and appearance resemble the larva of the Hessian fly and other 
species of Cecidomyia which have fallen under my notice, that I 
entertain no doubt it pertains to the same genus of insects. And 
when we see it infesting the same part of the wheat stalk with 
the Hessian fly, and producing much the same swollen appearance 
of the stalk, no person but one well acquainted with the habits 
of that insect would suspect that this was anything different. 
Rut the Hessian fly worm occupies a natural cleft or partition in 
the wheat plant, to wit, between the sheath which is formed by 
the base of the leaf, and the main or central stalk or culm. 
1 herefore, on drawing the leaf aside so as to part this sheath 
and separate it from the stalk, when it is stripped off downwards 
almost to its base, the Hessian fly worm is exposed to view. 
1 his may be done without any cutting or tearing of the plant. 
I he Joint-worm, on the other hand, lives in the parenchyma or 
