196 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 
cable to send any of the cocoons of the parasite until June and July; while in America 
the season was early, and by that time all of the caterpillars, as has already been stated, 
had pupated. In 1909 the season was rather early in Japan and correspondingly late 
in America; and, besides, through special effort, Prof. Kuwana was enabled to send a 
few thousands of the cocoons of the first generation, which reached the laboratory 
early in June. About 1,000 adults emerged from these cocoons after receipt, and the 
most of them were placed in one colony in a cold situation on the North Shore, where 
the caterpillars were greatly retarded, and where there were still some in the first 
stage. The remainder were colonized in warmer localities, where the caterpillars 
were one stage farther advanced. 
Immediate success followed the planting of these colonies. Within three weeks 
cocoons were found in each, and the number of parasitized caterpillars was gratify- 
ingly large. A very careful investigation was conducted, to determine the proportion 
which was attacked by native secondary parasites; and, while this was so large in one 
instance as seriously to i abae the success of the experiment, it was not solarge in 
the others. 
There were several thousands of this first generation known to have developed in 
the open upon American soil, which issued from the cocoons some four or five weeks 
after the colonies were established, but in only that one on the North Shore, where the 
caterpillars were in the first and second stages when the parasites were liberated, was 
there a full second generation. Here the larger caterpillars were again attacked, and 
an abundant second generation of the parasite followed. 
Meanwhile, additional shipments of cocoons of the second Japanese generation were 
received early enough to permit of a generation in the open upon the native cater- 
pillars, and several other, colonies were successfully established. It is known that 
there were many thousands of the parasite issuing in at least five different localities 
during August, but immediately thereafter they were completely lost to sight, and 
it is futile to hope to recover traces of them before another spring. 
Until the late summer of 1909 nothing occurred to indicate that this parasite would 
be likely to fly for any great distance from the point of its liberation; and, as has been 
already stated, it was looked for in vain in the summer of 1909 in the immediate vicin- 
ity of the colonies of the year before. In July, 1909, a strong colony was planted in an 
isolated woodland colony of gipsy moths in the town of Milton. It was rather confi- 
dently expected that it would attack these caterpillars so extensively as to destroy 
the major portion; but it was the cause of some surprise, when the locality was visited 
after the parasites of the new generation had mostly issued from the affected cater- 
pillars, to find a smaller number of cocoons than there were individuals liberated in 
the first place, and only about one-fourth, perhaps less, of the caterpillars attacked. 
The circumstance was as discouraging as anything which had gone before, and for a 
few days nothing happened to change its complexion. Then, to the intense surprise 
of the writer, Mr. Charles W. Minott, field agent of the central division, sent to the 
laboratory a bona fide example of the parasite, which had been collected in the Blue 
Hills reservation, upwards of a mile away. There was no possible source except the 
Milton colony, and a spread of upwards of a mile in something under a week was indi- 
cated beyond dispute. At almost the same time the brood of Monodontomerus was 
found for the first time in pupe of the gipsy moth in the field; and when the history of 
this species is considered, in the connection which it bears toward the circumstances 
surrounding the recovery of the Glyptapanteles so far from the point where it was 
liberated, the whole situation is altered. 
Granted that the parasite disperses at the rate of one mile in each week of activity, 
and that it is able to adapt its life and habits to the climate and conditions in America, 
the chances are, that, instead of looking for it in the immediate vicinity of the points 
of colonization, it is quite as likely to be found almost anywhere in the infested area 
