4 
reduced in both size and number, and in case of severe attack they 
become shrunken. 
NATURAL ENEMIES. 
Natural enemies are quite numerous, and most of them have the 
advantage of being double-brooded, whereas the joint-worm has but one 
annual generation. 
Probably the most efficient enemy of this species is a small, slender, 
four-winged fly, with a somewhat brilliant metallic-colored body and 
yellow legs. This has a very slight resemblance to an Isosoma, and, 
indeed, was described as [sosoma allyniit, now known as Hupelmus 
allynii French. A somewhat similar insect with metallic body and yel- 
low abdomen, Stictonotus isosomatis Riley, 
is very efficient in destroying the larve in the 
straw. Homoporus (Semiotellus) chalcidi- 
phagus Walsh and Riley and beyond a doubt 
other chalcidoids are also instrumental in 
holding the pest in check. These are all 
small four-winged flies, and a number of 
undescribed forms have recently been dis- 
covered. 
The larva of a small, slender, black and 
yellow carabid beetle (Leptotrachelus dor- 
salis Fab.) crawls up, descends into the 
stubble, and devours the [sosoma larvae, but 
. unfortunately its taste seems to be too ob- 
tuse to allow it to confine itself strictly to 
ie A ee Ce et ee Isosoma, and as a consequence it devours 
maining with the grain after Parasites as well as host. A mite, Pedicu- 
threshing (original). loides (Hetoropus) ventricosus Newp., is also 
an enemy, gaining access to the larvee precisely as does the beetle larva 
previously mentioned. 
PREVENTIVE MEASURES. 
There are no known remedies, but there are several preventive meas- 
ures that are not impracticable and are reasonably efficient. 
In the midst of the outbreak in Virginia, previously mentioned, a 
‘Joint Worm Convention’? was held at Warrenton, in that State, to 
devise means for controlling this pest. This body recommended a 
better system of farming, the use of guano and other fertilizers to pro- 
mote arapid growth and an early ripening of the grain, and the burning 
of the stubble, all of which are as advisable to-day as they were at that 
time. The most serious ravages are observed on thin or impoverished 
soils, especially along the margins of the fields infested. Anything, 
then, that tends to add vigor to the young growing grain will constitute 
a preventive measure, Burning the stubble, where this is practicable, 
