December, ’24] 
CHAMBERLIN: ALFALFA WEEVIL PARASITES 
625 
Although the methods of collecting parasites were fairly simple, the 
parasites were so scarce that much territory and material had to be 
examined before they were obtained in any numbers. 
Larval parasites were much easier to find than the egg parasites or the 
pupal parasites. The former were obtained by sweeping the weevil 
larvae from the fields and rearing or dissecting the parasites from them. 
The egg parasites were found by first dissecting the parasitic larvae from 
collected stems and afterward rearing them to maturity in wooden 
cells under direct observation in the laboratory. Only a small percent¬ 
age of the early dissections showed weevil eggs, and only a small portion 
of the egg masses found contained parasites. In studying parasites of the 
prepupa and pupae, it was necessary to collect large numbers of cocoons 
of the host. This was done chiefly by picking up the cocoons from the 
stubble in newly cut fields. This work was slow and tedious at best, and 
owing to the fact that many hosts were removed from the field by 
cultural practices, parasites, and disease, before the cocoons were spun, 
cocoons were harder to find than any other stage, and in our experience 
they could be collected profitably from very few fields. The study of 
cocoon parasitism was especially difficult owing to the great number of 
primary and secondary parasites in various stages that might be^ found 
in them. 
The chief parasites and some of their habits are described briefly 
below: 
Parasites of the Eggs 
Peridesmia phytonomi Gahan 1 
The larva of this pteromalid parasite feeds externally upon the eggs of 
Phytonomus posticus (Gyll.) and Hyper a punctata (Fab.). It appears 
to be widely distributed in Europe and is probably the most important 
of all the egg parasites. 
It may be found in either green or dry stems of alfalfa; when found 
in the latter it feeds more frequently upon the eggs of the clover-leaf 
weevil (Hypera punctata) . Adults issuing from egg masses of the clover- 
leaf weevil are usually much larger than those from alfalfa weevil egg 
masses, which is probably due to the plentiful food supply. Their larvae 
are found feeding on egg masses in the field from January to July ac¬ 
cording to the locality, and from January to May at Hyeres. Nothing is 
known of the number of generations since we were unable to rear the 
species in the laboratory or determine its life cycle by field observations. 
determinations of the Chalcidoid parasites by A. B. Gahan, of the Ichneumonid 
parasites by R. A. Cushman. 
