Proceedings of Eighth Annual Meeting 77 



roads and bayous separated into fields of varying extent by timber 

 growth and by undrained portions of the plantation, so that the 

 distances between the houses are greater than would be indicated 

 by the comparatively small amounts of land cultivated by each 

 tenant. The collections considered in this report are those taken 

 from the tenant houses only, those from the town of Mound not 

 being included. Thus the results apply strictly to the rural con- 

 ditions found on a cotton plantation in the delta. 



An indication of the malaria infection among the tenants on 

 this plantation is shown by blood examinations which were made 

 during August in 1915, 1916 and 191 7 and which gave an average 

 parasite rate for the three years of 16.5 per cent. This is of in- 

 terest for comparison with the Anopheles abundance on this place 

 and for further comparison with the parasite rate and Anopheles 

 abundance found in similar work elsewhere. 



The mosquito collections have been made inside and under the 

 tenant houses, in the stables, and in practically every kind of out- 

 building or resting place to be found about the tenant homes. The 

 houses of the tenants consist of two, three and four room frame 

 buildings which are raised an average of 2.5 feet off the ground,, 

 the sills being supported on wooden blocks. At most of the houses 

 there is a small stable or shelter for the work animals or cows, 

 there is usually a small cotton house, and often a corn crib, chicken 

 coop or shed. In all of these buildings mosquitoes are to be found 

 during the daytime, resting in the darker corners or on the walls 

 and ceilings. The majority of the resting mosquitoes are engorged 

 with blood and are easily caught in the collecting tubes. The 

 elevation of the houses from the ground provides a large open space 

 underneath which is frequented by dogs, chickens, and other do- 

 mestic animals and, as is shown, is the principal resting place of 

 adult Anopheles during the daytime. The stables are next in im- 

 portance in the relative abundance of Anopheles resting in them. 

 Fewer numbers are found inside the houses and in the out-buildings,, 

 other than the stables. 



During the seven years in which this investigation has been in 

 progress, over 1800 collections have been made at 90 tenants houses 

 and out-buildings, and from the various buildings at these locations 

 a total of 132,167 Anopheles have been collected, counted, and classi- 

 fied as to species, sex, and resting place. The majority of these, 

 98.53%, were Anopheles quadrimaculatus , 1028 specimens or 0.84% 

 were Anopheles punctipehnis and 836 specimens or 0.63% were 



