*43 



ensack Valley, cantator continue to breed throughout the season 

 and the sollicitans breeds, if at all, in very small numbers. 



The fact that the great cedar swamps of South Jersey do not 

 breed the economic species of mosquitoes has been left unex- 

 plained, and, in the course of efforts to determine the cause, 

 larvae of various stages of all the principal economic species 

 were placed in cedar-swamp water, and without exception all 

 died in this water in less time than they did in distilled water, 

 showing that there is something in the water which is unfavor- 

 able to them,. What this condition is the investigation did not 

 go far enough to show. 



Many problems of much importance to the practical work 

 of controlling mosquitoes still await solution. Among these is 

 the discovery of a satisfactory larvicide. Such a larvicide should 

 be harmless to water plants, not injurious to the larger domestic 

 animals and man, and should be of such a character that it can 

 be placed in a pool and will remain effective in that pool through- 

 out the season regardless of the fact that the pool may be dried 

 up and refilled many times. 



Another important problem awaiting solution is the devising 

 of a method by means of which the remnant of mosquitoes left 

 by the methods of practical work now in use may be eliminated. 

 This problem can, it seems to the writer, be best approached 

 through a study of the food and ovi-position responses of the 

 important species. 



The largest of all the problems yet remaining is that of com- 

 pleting the initial work on the salt marsh. To get a proper view 

 of this problem it is necessary to divorce ourselves from the 

 fresh-water mosquito problem. To do this we should recall 

 that the fresh-water species are only slightly migrational and 

 affect only the territory in which they are bred, or at most only 

 a very limited area adjacent thereto, and that their control, there- 

 fore, constitutes a proper and practicable charge against the 

 local community. 



The salt-marsh species, on the other hand, in the course of 

 their long flights cover so large a part of the State that their 

 removal would be a matter of importance to the whole popula- 



