20 
BULLETIN 124, U. S. DEPARTMENT OE AGRICULTURE. 
of these parasites issued several clays later, or 3 per cent. On July 
28 Mr. Newton, encouraged by his first efforts, collected 31 eggs that 
appeared to be parasitized. Twenty-six of 
these produced, in the course of five days, 76 
parasites, or nearly 3 to each egg. Seventeen 
freshly laid eggs were exposed to female para- 
sites by Mr. Newton on August 1, and on 
August 8 eight of these produced 24 adult 
parasites, showing the length of the combined 
egg, larval, and pupal stages to have been seven 
days. Nine failed to be parasitized, and one 
produced 5 parasites in six days. On August 
16 Mr. Wilson collected 19 eggs, 60 per cent 
of which were parasitized. 
It is thus seen that this tiny parasite is of 
considerable benefit in reducing the numbers of 
the alfalfa caterpillar. From the records it 
seems that the increase of the parasites from 
July to August was quite rapid. The fact that 
the life cycle is of so short duration is partially 
responsible for this, as it doubtless gives a 
chance for two broods of parasites upon the eggs of one generation of 
Eurymus. 
HYMENOPTEROUS PARASITES OF THE CATERPILLARS AND CHRYSALIDS. 
Four species of hymenopterous parasites of the caterpillars 
and chrysalids were found. Specimens of a Limnerium were reared 
Pig 
—Trlchogramma 
minutum, a parasite of 
the eggs of the alfalfa 
butterfly, in act of 
oviposition in an egg 
of the brown-tail moth 
(Euproctis chrysor- 
rhcea). Greatly en- 
larged. (From How- 
ard and Fiske.) 
Fig. 8. — Limnerium n. sp. 
an ichneumonid parasite of the alfalfa caterpillar 
Greatly enlarged. (Original.) 
Adult. 
by the author at El Centro, Cal., in 1910, and what is supposedly 
the same species was reared in considerable numbers by Mr. L. P. 
