PARASITES HIBERNATING IX BROWN-TAIL WEBS. 
277 
localities in which Pteromalus had been colonized. Several thou- 
sands were thus collected in 1909-10 (as may be seen by reference to 
Table X) and a much larger series of collections was planned for the 
winter of 1910-11. 
On the face of the results of this work during the two previous 
winters, nothing was much less likely than that Pteromalus should 
be recovered from any of these collections of nests. When a few 
specimens of a ptemmalid which looked very much like it did issue 
early in December, they were accorded a rather cool reception, and 
made to identify themselves b\- reproducing upon hibernating cater- 
pillars of the brown-tail moth in confinement. Before such identi- 
fication was complete, it was rendered unnecessary through the issuance 
of considerable numbers of what could no longer be questioned as the 
true Pteronxilus ((jrajnis from no less than 10 lots of nests collected 
in different towns scattered all the way from Milford. Mass., down 
near the Rhode Isiand line, to Dover and Portsmouth, X. II., just 
across the Piscataqua River from Maine. At the time of writing 
they are still emerging from the collected nests, and the extent of 
their dispersion is not yet known, but Mr. II. K. Smith, who is attend- 
ing to the rearing cages, has prepared a map (Plate XXVi .showing 
lie location of the original colonies as well as the towns from which 
recovery has been made the present winter. 
Sufficient data have already been accumulated to make certain 
the astounding fact, that as a result of the colonization work • •<>n- 
ducted between 19(H) and 1 ( .M)S, the parasite, is now thoroughly 
established over a territory which undoubtedly includes portions of 
four States, and during the period of its dispersion it spread itself out 
so thin as to make its recovery impossible except in the immediate 
vicinity of the colony sites, and for a short period immediately fol- 
lowing colonization. Until this time Monodontomerus has held the 
record for rapid dissemination, but this record is now eclipsed. 
It is impossible to determine whether the first of the colonies were 
after all successful, or whether they actually died, as was supposed, 
and success finally resulted from the very much larger colonies in 
1908. If the early colonies lived, it means that no less than four 
years elapsed before any evidence to that effect was forthcoming. 
This fact, in its relation to circumstances attending the colonization 
of another parasite, Apanteles fulvipes, which seems not to have 
succeeded in establishing itself any more than Pteromalus appeared 
to have established itself as a result of those early colonizations, will 
sustain some hope for the ultimate recovery of this parasite until 
1912 or 1913. 
If, on the other hand, the establishment of Pteromalus resulted 
from the very much larger and in every way satisfactory colonizations 
of 1908, it may mean, in its reference to Apanteles fulvi pes, that very 
