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Status of Parasites 
Lydella stabulans var. grisescens R.D . — This tachinid is the most 
widely dispersed of the exotic corn borer parasites. In the Lake States it 
was the only parasite known to be attacking the corn borer in appreciable num- 
bers up to the close of the 1940 season, and in this region it was present only 
for a limited distance inland in the vicinity of marshland bordering Lake Erie 
from the southern city limits of Detroit, Mich., to the Huron River west of 
Sandusky, Ohio, It is not known to have msi ntained itself near the marshland 
bordering any of the smaller lakes or ponds or at any other point in the Lake 
States area. The localities in which the parasite occurs comprise only a small 
part of the infested area, but at certain points as shown by the 1940 surveys 
and probably wherever marshland is abundant on the Lake Erie shore, high con- 
centrations of the parasite exist. At Perkins Township, Erie County, Ohio, and 
at Erie Township, Monroe Co., Mich., two points selected as being representative 
of the Lake Erie marshland environment, a considerable increase in the percent- 
age of parasitization by L. grisescens over that of 1939 was noted. At the 
former point one collection showed a parasitization of 85.1 percent, and the 
average for the area surveyed was 48.5 percent. 
In the Eastern area L. grisescens was taken at all ^points surveyed and 
was either the most abundant or the second most abundant parasite in each case. 
In southeastern Massachusetts the percentage of parasitization was double that 
of 1939. In 11 of the collections from this locality over 25 percent of the 
borers had been killed by this dipterous parasite. In the Connecticut River 
Valley in Massachusetts, where Lydella grisescens was released in 1935, the 
1940 surveys show the parasite to be well established. In central Connecticut, 
in the vicinity of Hartford, this tachinid was slightly more prevalent we st of 
the Connecticut River but was present in small numbers throughout the 415 
square miles of the surveyed area. It was also found to be. well established 
at Haddam, Middlesex County, Conn. , where a release had been made in 1935. L. 
gri sescens . released in Atlantic Township, Monmouth County, N. J., in 1935, was 
found to be well established, increasing, and spreading. At Burlington Town- 
ship, Burlington County, H. J. , a recently established release point L, 
grisescens was the only parasite recovered. Parasitization by it was low but 
considerable dispersion was evident. 1^ gri sescens was also the only parasite 
reared from borers taken from the Lee, Accomac County, Va., locality. 
Inareolata punctoria Roman .-- This ichneumonid parasite was recovered 
at only one point in the Lake States, namely, in the vicinity of the Cattaiv 
augus Creek, in the Cattaraugus Indian Reservation, N. Y. The limited survey 
at this point did not permit exact definition of the area in which the para- 
site was present. Because the parasite has been recovered in this locality 
whenever observations have been made, and in view of the decided increase in 
its abundance since the last recovery in 1935, it appears probable that Ij_ 
•punctoria has become a permanent part of the fauna of the locality. 
At the Erie Township, Monroe County, Mich., release point, where this 
ichneumonid persisted for 5 years following its last release, no recovery has 
been made for 3 years. However, since the parasite has been noted in miscel- 
laneous collections in the vicinity of Toledo in 1938 and 1939, it is possible 
