-623- 
at the actual points of release, which are within 10 miles of the center of the 
area in which the parasite is now well established, no parasites have been re- 
covered* > . 
These observations indicate that G he 1 onus annul ^.pes can exist only in more 
or less restricted ecological areas and that the success of colonization attempt? 
depended to a large .extent on whether or not the release was made near the more 
favorable part* of one of these areas* As the factors which limit this parasite 
to specific areas were not readily determinable, and in order to establish the 
practical utility of close colonization as a measure conducive to more rapid 
build-up of parasite populations than that obtained by dispersion from widely 
separated release points, tho colonies in the 1939 release areas were so closely 
spaced that there would be a high probability of locating 1 or more colonies neai 
tho center of favorable ecological islands, should any be present in the region. 
During the season 4g releases, totaling 47,724 parasites, were made in Connecti- 
cut and 23 releases, totaling 22,826 adults, wore made in the Hudson River Valley 
N. Y. 
In order to test the effect of climatic changes experienced during recent 
years and the influences that might restilt from the prevalence of a two-genera- 
tion strain of the borer in the lake States, 4 colonies totaling 4,476 adults of 
C. annul ipes . were released in northeast earn Indiana. 
Field examinations made at the time of the releases of C. annul ipes in the 
lower Hudson River Valley showed that, although host eggs were still present in 
small numbers in the fields, the releases here wore later than optimum for good 
synchronization. This probably was also true for the releases of this species 
in Indiana, where information received from State officials indicated that the 
peak of host oviposition occurred about June 26, although the parasites wore not 
released in this district until Juno 29* All other releases appear to have been 
very well synchronized with the presence of the borer in a favorable stage for 
attack. The synchronization of the large releases of C.* annul ipes in Connecti- 
cut with the presence of corn borer eggs was particularly satisfactory, host eggs 
being present in unusually large numbers. All adults of Chelonus annulipes re- 
leased consisted of individuals bred on ffphestia kuehniella Zell, at the Toledo, 
Ohio, corn borer laboratory* The original breeding stock of the parasite was 
obtained from corn borer larvae collected at the point where this parasite is now 
well established in southeastern Massachusetts* 
The polyembryonic parasite Macrocentrus gifuensis Ashm. . which attacks youn 
corn borer larvae, is well established in a locality in eastern Massachusetts and 
it was desired to extend the distribution of this species, although no large-scrX 
program was attempted. Colonies of 1,902 and 2,177 adults were released at 
Kingston, Ulster County, N. Y*, and in Atlantic Township, Monmouth County, N. J. 
Smaller releases were made in Burlington Township, Burlington County, N. J., wher; 
this parasite had been released previously. The adults of M. gifuens is released 
during the first half of July were reared from borers collected in Massachusetts 
in the spring of 1939 to supply this parasite. The parasite releases made in 
ugust against the second generation of the borer were made possible by parasites 
obtained incident to parasite-field-status studies at Taunton, Mass., on the first 
generation *>f the borer. 
library 
9TATE> PLANT BOARD 
