roc; Parasites of tiik tnpsv moth. 
185 
began to increase rapidly in numbers with each succeeding generation. 
By AiiLTu-t there were enough to make a small colony in the open 
possible without depleting the laboratory stock to a serious extent, 
and firsi one and later several small colonies were established in 
various localities in the moth-infested area. 
At the same time reproduction work was continued on an ever- 
increasing scale at the laboratory, and by the iirst of the next year 
no less than 1,000,000 individuals, at a conservative estimate, were 
present in our rearing cages. Further attempts to increase this 
number were not successful, on account of the difficulties attending 
the handling of such an immense number at a time when the hatching 
of the host eggs followed too soon after their removal to high tem- 
perature. 
The numbers in the laboratory Buffered no decrease, however, and 
by the end of March colonization work on an extensive scale was 
begun. The parasitized eggs were divided into 100 lots, each of 
which contained approximately 10,000 of the parasite, and these 
were distributed to agents of the State forester's oflice, who placed 
them in the held in the hope and expectation that the parasites 
issuing from them would reproduce immediately upon the gipsy-moth 
eggs before the latter hatched. 
There was also a large quantity of parasitized eggs remaining, and 
these were placed in cold storage in the hope that the emergence of 
the brood might be retarded until the fresh eggs of the gipsy moth 
should be available for attack in the latter part of the summer. This 
hope was not justified, because when the time came and the eggs 
were taken from cold storage not a single living parasite remained. 
In Table IX are summarized the results of the reproduction work, 
as conducted in the Laboratory from April, 1909, to the winter of 
1909-10, and the dates when the first colonies were planted in the 
late summer and fall are therein indicated. 
Table IX. — Jictnlts of n ■•production irnrk uitlt Scfudius. 
Gcner- 
ation. 
N u in 1 >er and source of pan • n 1 1 . 
Reproduction work 
begun. 
Emergence of prog- 
eny. 
Total 
nuinlter of 
progeny. 
Colo- 
nized. 
Began. 
Ended. 
First 
11 from imported egg masses. . 
lit from first generation 
645 from second generation 
1.350 from third generation 
1.01'.* from fourth generation... 
3,00ti from fif t h generat ion . . 
7,355 from sixth generation.. . 
20,784 from seventh gener- 
ation. 
199.512 from eighth gener- 
ation. 
204, too from ninth generation. 
Apr. 19 
Mav 19 
June 23 
July 10 
Aug. It'. 
Sept. 11 
Oct. 5 
Oct. 29 
June 14 
July If. 
Aug. 10 
Sept. 7 
Sept. 29 
Oct. 25 
Nov. 15 
114 
iw."> 
1,350 
11.999 
•;. 
12.723 
35.423 
l 219, (.27 
1 1,028,301 
I 9,<U 779 
S.vond.. 
Third.... 
Fourth... 
Fifth.... 
Sixth 
Seventh.. 
Eighth... 
Ninth.... 
Tenth.. 
May 19 
Julv It. 
Aug. 16 
Sept. 11 
10. 9M) 
3.2*0 
5.3U.S 
5,639 
20,115 
733, 967 
•'mi. 7A9 
Sept. 30 
Oct. 25 
Nov. 21-Dec.21 
Tan. 
1 Estimated. 
