JOINTWORM FLIES. 19 
LIFE HISTORY. 
As this grass grows naturally in waste places and along fences its 
jointworm enemy does not depend upon cultivated areas to maintain 
itself. It winters in the old seed stalks as pupa, the adult emerging 
near the middle of May. The species is normally thelyotokous, 
males very rarely occurring. 
SPECIES INFESTING WILD GRASSES. 
In the preceding pages the writer has given briefly some of the 
more important facts relating to all the species at present known to 
infest our grains and cultivated grasses. It may appear at first 
glance that wheat has rather more than its share of species, especially 
since it is our most important small grain. On the other hand, the 
genus Elymus, a wild grass, is the home of nine species, eight of which 
are gall-formers ; Agropyron sp., another wild grass, has four species, 
three of which are gall-formers. The species infesting the wild 
grasses will be dealt with very briefly. A good many of them may 
lay a just claim to some consideration from an economic standpoint, 
from the fact, as previously stated, that they have parasites in com- 
mon with the more important economic species. 
HARMOLITA MACULATA Howard. 
Howard (8, p. 15) described this species as Isosoma maculatum 
in 1896 but nothing was known then of its life history. In re- 
cent years it has been collected by various members of the branch of 
Cereal and Forage Insect Investigations. The writer has reared it in 
confinement since 1912. It has persistently refused to breed in any 
host other than grasses of the genus Bromus. It does not form galls 
but lives in the walls of the plant stem, particularly of cheat (Bromus 
secalinus). The cheat stem is almost solid near the base, at least just 
above the lower joints, the walls being very thick. The egg (fig. 8, d) 
apparently is deposited in the walls of the stem somewhat like the egg 
of tritici and the larva excavates a little tunnel about half an inch 
long just above the joint (PI. V, B). There are sometimes two or 
three to an internode. It is a very widespread species and un- 
doubtedly occurs wherever cheat or other species of Bromus are 
found. 
There is only one generation a year. The species hibernates in 
the larval stage, pupates in the spring, and the adults emerge in May. 
It is arrhenotokous under control conditions though in nature both 
sexes occur. 
HARMOLITA ATLANTICA Phillips and Emery. 
Harmolita atlantica (10, p. 461) is a species which the writer first 
reared near Eichmond, Ind., in 1909. A few specimens have been 
