1946] Dragonflies as Enemies of the Stable- fly 51 
season, great numbers of dragonflies appeared in the air above 
the camp and within a few minutes the stable-flies had dis- 
appeared. Moreover they did not reappear during the several 
remaining weeks of our stay at Cedar Lake, although each 
evening numerous dragonflies were to be seen feeding in the air 
above us. 
The dragonflies were not identified, but appeared to be a large 
species of ^Eschnidae which appeared most abundantly at dusk, 
darting about in such numbers that we could occasionally hear 
the impact of their bodies as they collided in the air. Midges 
and mayflies are extremely abundant since there are endless 
opportunities for them to develop in the lake as well as in the 
spruce swamps and the other marshy areas characteristic of the 
region. Dragonflies are likewise a conspicuous element of the 
insect fauna just as they are along our southern Atlantic and 
Gulf coasts. The stable-fly population at Cedar Lake, however, 
cannot compare to the almost incredible numbers which regu- 
larly infest our southeastern beaches. 
The stable-fly is undoubtedly an old world species, possibly 
native to India, but was reported to be abundant in Philadelphia 
as early as 1776, and appears at present to enjoy a distribution 
about as wide as that of any insect. 
POLYDRUSUS SERICEUS SCHALL. 
This European species is listed in the Leng list as occurring 
in Indiana. In 1941 from May 25 to June 22 I took a number 
of them on poplar and again in Framingham in 1943 they were 
abundant on Corylus americana , poplar and maple near the same 
locality. This year (1945) they were again abundant especially 
on Corylus about June 10th. The European species of these 
green weevils are very numerous, or at least the names are, and 
the present species resembles many of them. Superficially they 
resemble large Polydrusus impressifrons Gyll., Phyllobius pyri 
L. and also the green form of Scythropus elegans Coup. Phyl- 
lobius glaucus Scop, is recorded from “Can.” but probably this 
is a misidentification of P. pyri since the specimens from Mr. 
William Procter taken at Bar Harbor, Me., were first identified 
as P. glaucus. — C. A. Frost 
