185 



heaps, cellars, dried up cess- pits, damp bricks, manure heaps, disused 

 poultry houses built of bricks and clay, coAvsheds, stables, latrines, etc. 

 The bulk of this material yielded negative results, but a few larvae and 

 pupae were found in it and more adults developed from the same 

 material stored in jars. The comparatively small number of larvae 

 and pupae found is probably accounted for by their great similarity to 

 their surroundings rendering detection extremely difficult. The 

 species found were Phlehotomus papatasii and P. minutus, which 

 apparently complete their life-cycle without an animal host during 

 the preliminary stages. The conditions of breeding-places may vary 

 slightly with different species, but given favourable condition 5, such 

 as darkness, a certain degree of moisture and the presence of decaying 

 vegetable matter, the particular site is evidently immaterial. To give 

 rise to favourable conditions, decaying vegetable matter must remain 

 undisturbed for some time, but darkness is not essential for the breeding 

 of P. miniUus. 



Mayne (B.). The ultimate Seasonal Infection of Malarial Fever, with 

 the Mosquito Carrier as the Indicator. -U.S. Public Health Repls., 

 Washington, D.C., xxxiv, no. 35, 29th August 1919, pp. 1989-1972. 



To ascertain the latest date of infection of mosquitos, for use as an 

 indicator to determine, the discontinuance of sanitary protective 

 measures against malaria [see this Review, ser. 13, B, p. 182], 

 investigations have been carried out in Alabama and Louisiana during 

 1916 and 1917 respectively. 



In Alabama a total of 1,377 individuals of Anopheles quadrimaculatus 

 and A. punctipennis were collected, of which 709 were examined. The 

 first infected mosquito appeared on 21st September, the last on loth 

 November, the latter being an individual that had been caught on 1st 

 November and kept at room temperature for a fortnight to allow of 

 maximum development of any parasites present. In this district 200 

 persons examined gave a malaria index of 18"6% in September. The 

 temperature records for the period during which mosquitos were 

 captured show a range from a minimum of 20° F. to a maximum of 

 W F. 



The temperature in Louisiana, from August to December 1917, which 

 was the period during which the captures were made, varied from 26° F. 

 to 100° F. A preliminary survey among 250 persons revealed a history 

 index of 83% and a parasite index of 22%. Of 746 mosquitos 

 captured, one infected individual was A. crucians and 17 A. quadri- 

 maculatus ; the last two infected individuals were caught on 20th 

 October and 1st November and were both A. quadrimaculatus. The 

 biological conditions generally considered normal for infection 

 continued to the last week in November ; biting by Anophelines was 

 reported up to 9th and true hibernation was not noticed until 23rd 

 November. The latest date of infection in mosquitos may be assumed 

 as 1st November in Louisiana for 1917, but this does not apply else- 

 where at similar latitudes nor in the same locality for other years. 



Similar studies must be carried out in many more malarial zones 

 before generalisations can be made as to the conditions bearing 

 on malarial epidemiology. To ascertain from the knowledge gained 

 from these observations what would be a safe date to discontinue 



