1018 ENTOMOLOGJCAL SOCIETY. 49 



leaves or in the ground. Not do the horns of H. guttivitta and the hump of 

 S. concinna show signs of becoming vestigial, for both are well nourished and the 

 latter bears moveable spines. 



Predaceous insects are the usual enemies of small caterpillars, and birds of 

 full grown larv£e. To escape the former the horns of Heterocampa are well 

 adapted, but why should they suddenly disappear at the first moult? The marked 

 increase in size of S. concinna during the last larval stage may call for more con- 

 spicuous warning colour that the passing bird may more easily see that the insect 

 is not good food. Whatever be the reasons, the entomologist who observes the 

 development of Notodontian larvas must be impressed by the protection God gives 

 these strange creatures against the enemies who prey upon them. 



EVENING SESSION. 



The evening meeting was opened at 8 o'clock with an address of welcome by 

 Dr. Harrison, Principal of Macdonald College. 



Owing to the fact that he would be unable to remain for the whole of the 

 evening session Dr. Hewitt took this opportunity of introducing the symposium 

 in " Canadian Entomologists and the War," the discussion of which was to take 

 place at the smoker later in the evening. 



The public lecture on " The Problem of Mosquito Control " was then delivered 

 by Dr. T. J. Headlee, State Entomologist, New Brunswick, N.J, 



THE PEOBLEM OF MOSQUITO CONTROL. 



Thomas .T. Headlee, Ph.D., Entomologist of the Nevs^ Jersey Agricultueal 

 Experiment Stations and State Entomologist. 



Introduction. 



While interest in anti-mosquito work is now found in nearly all parts of the 

 world, it is engaged in most cases with very limited areas of country. No doubt 

 this is due to the fact that the source of interest is usually the hope of eliminating 

 insect-borne diseases from limited areas. 



Anti-mosquito work in New Jersey does not have its roots in the desire to 

 destroy diseases. Malaria, which with us is the only mosquito-borne disease, occurs 

 in only a few very limited areas and forms in each case a strictly local problem. 

 Interest in mosquito control in New Jersey arises from the desire to make the 

 state entirely comfortable and desirable for its citizens. 



The north-eastern end of the state is rapidly being transformed from low- 

 priced farm land into urban property and the mosquito pest, such as would come 

 from the unprotected salt marsh, would seriously interfere with and delay that 

 process. In the counties of Hudson, Bergen, Essex, Union and Middlesex, each 

 of which have some thousands of acres of salt marsh within its borders, in the ten 

 year period from 1900 to 1910, 60,000 acres of farm land were transformed into 

 urban property, and the growth during the last seven years has not been less rapid. 

 Within range of these salt marshes lies the County of Passaic, which is. really a 

 member of this group, but which has no salt marsh. 



