REPORT ON MOSQUITOES. 139 



advantage of the oils that form surface fihns and do not mix with 

 the water is that it is eas}- to determine the amount needed, and 

 that for a given area it is silways the same whether the pool is 

 deep or shallow. Another point in their favor is that the action 

 is as positive against pupae as against larvae. The disadvantage 

 is the ease with which a film is destroyed and the short time that 

 is needed to form a good breeding place after the application is 

 once made. 



The advantage of those materials that actually poison the water 

 is that the latter is rendered unfit for larvae so long as it re- 

 mains or is not materiallv diluted. The disadvantage is that as a 

 rule they do not act promptly or at all on the pup£e. 



Phinotas oil and the soluble crude oil belong to both types and 

 should b,e, theoretically, the best of all. But both are too destruct- 

 i\e to ac[uatic life generally, where such exists, and are not as 

 active disinfectants as some of the Cresol preparations for gutters, 

 etc., besides being- dirty. 



. Conditions varv, and no two can Ije dealt w'ith in just the same 

 manner. There are plenty of tools to work with and that should 

 be selected which fits best. 



At the risk of repetition, I will say again, that wherever perma- 

 nent work is possible, these larvicides and their applications should 

 be regarded as makeshifts only, until the more radical improve- 

 ments can be made. 



REPELLANTS. 



As there are yet some moscjuitoes in New Jersey, and as it 

 may be necessary to go sometimes to places where there are a 

 great many, it may be adantageous to know how^ they can be kept 

 off, to a greater or less extent at least. There are some fortu- 

 nate persons whom the insects seem for some reason to avoid, 

 and as the exemption mav be due to some peculiarity of per- 

 sonal odor, he that is subject to attack attempts to hide the 

 source of that attraction behind some strong smelling oil or 

 smoke. 



Tobacco is a well known refuge for the aftiicted, and he who is 

 able to keep himself surrounded by a cloud of smoke from a 

 cigarette, cigar or pipe, may sit comfortably on a Barnegat hotel 

 piazza in the evening, provided he does not wear low shoes. 



For those to whom this refuge is denied there are the Chinese 

 and Japanese punk sticks or mosquito cones of various sorts ; all 

 burning slowly and forming an aromatic smoke that is really a 

 considerable protection. In the compositions made up into c<Mies 

 or pastilles, napthaline and pyrethrum usually enter as the chief 



