PARASITES HIBERNATING IN BROWN-TAIL WEBs. 269 
In the spring of 1906 some 40 large tube cages (PI. X, fig. 1), each 
capable of accommodating several thousand nests, were constructed 
after the model of a cage which had been successfully used for a some- 
what similar purpose in California. Hardly had the nests been placed 
in these newly constructed cages before the caterpillars began issuing 
in extraordinary numbers, and with them many thousands of adult 
parasites, representing a great variety of species. Monodontomerus 
ereus was about the first to issue, and with it was a quantity of 
Habrobracon brevicorns. A little later Pteromalus egregvus (fig. 65) 
appeared in an abundance which exceeded that of all the other para- 
sites taken together, and it was followed shortly afterwards by 
swarms of its own little parasite, determined by Dr. Ashmead as 
Entedon albitarsis. 
Fic. 65.—Pteromalus egregius: Adult female. Greatly enlarged. (Original.) 
Mr. Titus at once recognized Entedon as hyperparasitic and pro- 
ceeded as assiduously to destroy it as he was assiduous in saving the 
Pteromalus. Of the myriad of other parasites issuing, the vast 
majority were represented by so few individuals as to render it very 
improbable that any among them were enemies of the caterpillars of 
the brown-tail moth. Nearly all of the more common species, aside 
from Pteromalus and Entedon, were representative of genera or 
groups of genera well known to be parasitic upon Cynipide, of which 
large numbers issued from the galls on oak leaves that had been used 
by the caterpillars in the construction of their nests. There remained 
as possible parasites of the caterpillars of the brown-tail moth only 
Habrobracon brevicornis, Pteromalus egregius, and Monodontomerus 
xereus. 
It looked for a time as though the Habrobracon might be para- 
sitic upon the hibernating caterpillars, and quite a large number of 
