MINUTES OF BLEVENTH ANNUAL MEETING i ly 
for 1916. The equipment of the new vivarium has now been 
brought into working order, and a series of experiments has 
been made upon the effects of weather conditions on the rate of 
development, number of individuals, and general success of 
several species of insect pests. The work to date shows that in 
addition to temperature, which is well known to have marked 
effects, air movement (wind) and humidity have effects which 
indicate that the relation of weather to insects is more com- 
plicated than is commonly supposed. These experiments have 
been made on cabbage butterflies, chinch-bugs, and pupae of 
the codling-moth. Those on the last are now being repeated 
under very carefully controlled conditions, with a view to 
determining the optimum humidity for each temperature. The 
chinch-bug, one of the most destructive Illinois pests, is so 
sensitive to all sorts of conditions, such as kind of food, too 
little moisture, too high temperature, too rapid air-movement, 
and the like, that it is extremely difficult to breed it in captivity. 
The length of time required to enable this insect to pass from 
the egg to the adult is modified by external conditions to a 
greater degree than in most other species. These experiments 
have been carried far enough to show that the chinch-bug can 
reach the enormous numbers in which it sometimes appears, 
only under certain very limited conditions. It is hoped that 
by means of further experiments, these conditions may be more 
precisely determined than has been possible with field observa- 
tions alone. 
Dr. W. B. McDougall, of the Botanical Department of the 
University of Hlinois, began, during the summer of 1917, a 
study of the vegetation along the Vermilion River in Vermilion 
county. The area covered includes bottomland, upland, and 
much eroded Iand between. The region is all underlaid with 
coal, and any study made there necessarily involves important 
questions concerning the relation of the mining industry, 
forests, and the practice of agriculture to each other. It is pro- 
posed to study the physiographic ecology of the region and 
at the same time to give as much attention as practicable to 
the biotic factors involved. It is hoped that a comprehensive 
report may be made at the end of the season of 1918. 
