JOINT WORM FLIES. 15 
in 1885. Webster observed this species in rye "stalks in Indiana, 
Ohio, and Virginia in 1904. Since that time the writer has collected 
it in Ohio, Indiana, and Pennsylvania. 
MANNER OF INJURY. 
The larva works in the center of the stem just at the joint, in the 
same way as does the summer form of the straw-worm. The writer 
has never seen a heavy infestation by this species. 
HOST PLANTS. 
The writer has bred this species for 8 years in confinement and 
made various attempts to induce it to breed on other hosts, but with- 
out success ; it confines itself exclusively to rye. 
LIFE HISTORY. 
Starting originally with 2 females and 1 male, the writer has 
reared this species in confinement since 1911. All successive gen- 
erations are the progeny of these individuals, and among several 
hundred specimens reared only 1 or 2 males have appeared. 
There is only one generation a year and the larvse remain in the 
old stubble until spring when they change to pupae, the adults emerg- 
ing about the middle of May. The egg is shown in figure 7 at b. 
SPECIES INFESTING THE CULTIVATED GRASSES. 
THE TIMOTHY STRAW-WORM. 1 
The timothy straw-worm has been known since 1894, when it was 
described by Ashmead (1) . Nothing seems to have been learned about 
its life history until recent years. It is very widely distributed and 
undoubtedly may be found wherever timothy has escaped from culti- 
vation and grows wild. It is not dependent, therefore, upon arti- 
ficial plantings of timothy. 
MANNER OF INJURY. 
H. albomaculata occupies the center of the stem, rasping the inner 
walls and feeding upon the juices of the plant (PL IV, C). Usually 
it is found just at or slightly above the second joint from the root 
though it may occur at any joint or at every joint. The injury is 
apparently not sufficient to decrease the hay crop materially, although 
a heavy infestation certainly would have a considerable effect in 
lessening the seed crop. 
1 HarmoUta albomaculata Ashmead. 
