86 N. J. Mosquito Extermination Association 



The catch data throughout are divided as to whether the insects 

 were caught under the house, inside the house, or in barns. The 

 catch under the houses was at the rate of 229.6 specimens per 100 

 minutes of time consumed in making a total of 176 collections; 

 for the inside of houses the catch was at the rate of 63.5 specimens 

 per 100 minutes of time, while the total number of collections was 

 162; the catch in barns was at the rate of 171. 2 specimens per 100 

 minutes of time consumed, while the number of collections was 

 170. In brief, there is very little difference in the number of col- 

 lections, all of which were probably made at the same time, while 

 the range in the relative number of specimens was highest under 

 the houses, indicating a serious potential possibility of infection to 

 those inside the houses; there was a material reduction, no doubt, 

 in part at least, as the result of effective methods of screening ; while 

 the catch in the barns was midway between the two. The results 

 may be considered of practical value in that they clearly indicate the 

 relative mosquito frequency in the vicinity of houses, and the reduc- 

 tion of such frequency in the houses as the result, no doubt, of pro- 

 tective measures. 



In a somewhat similar manner the larval production record has 

 been ascertained. For the whole area 231 collections were made 

 •during 1920, representing 2,620 dips, producing 2,261 larvae and 28 

 pupae in the a water area of approximately 35,000 square feet. The 

 relative production record for the year was, therefore, 86.3 larvae 

 per 100 dips, or 64.4 larvae per 1,000 square feet of area. This 

 information is, of course, available by months and for all the dif- 

 ferent stations under observations, but are indications of the method 

 wihch would seem sufficient for the present purpose, for it seems of 

 the first importance that some kind of standardized form of relative 

 mosquito density and of relative larvae production should be 

 adopted. At the present time no corresponding comparative data 

 for other areas are available, but extended over a period of years 

 the present method should be of considerable practical usefulness 

 for the section under review. 



Much, of course, has been published in the nature of mosquito 

 surveys, but as a rule such investigations are limited to the specimens 

 found, and while the actual numbers of insects are given, no stand- 

 ardized method of relative density has thus far been found feasible. 

 The question becomes of considerable practical importance in the 

 correlation of such observations to medical and economic data. The 

 medical statistics which have thus far been collected are only tenta- 



