157 



■differences of level. This water is sometimes as much as 30 feet below 

 the surface, whence it is raised by a very primitive system of buckets 

 on long levers for irrigation purposes. Most of these wells are in daily 

 use and the water is so much disturbed in them that they cannot serve 

 as mosquito breeding places ; others are hardly ever used, and in these 

 mosquitos can and do breed. The stagnant pools produced by the 

 outcrop of the subsoil water are nearly always close to groups of palms 

 and provide good breeding grounds for mosquitos. The winter, spring 

 and summer of 1915 were exceptionally rainless, so that the pools were 

 reduced to a minimum and no Anophelines and very few Culicines were 

 sent to the Station. Heavy rains fell in September and October and 

 great numbers of pools of water, which persisted for several weeks, were 

 formed ; these, so far as they were examined, yielded Cuhcine larvae 

 only. The area has always been known as malarious and the author 

 points out that the prevailing notion that the oases of the Sahara are 

 free from malaria is entirely erroneous; in this particular oasis, 31 

 infected subjects were found out of 121 examined, the majority of them 

 being children. At Beni-Abbes itself, the conditions of which are 

 described in detail with a plan, a few female Anophehnes were caught 

 in July and November ; the Culicines never completely disappeared, 

 and their larvae were always to be found in fire buckets and other 

 receptacles. The very mixed population, both civil and mihtary, 

 always provided a good reservoir, and of 77 persons examined 45 carried 

 the parasites in their blood. The French population protect their 

 houses with wdre gauze, and measures have been taken to convert 

 into a garden a marshy area which bred mosquitos in quantity. 



The form Of trypanosomiasis in horses known locally as debab was 

 much less prevalent in 1915 than usual, and its prevalence appears to 

 be more or less directly proportional to that of various species of 

 Tabanids, the exceptional dryness of 1915 being very unfavourable 

 to the development of these flies. Camels which traverse the areas 

 infested by them appear to be specially liable to trypanosomiasis. 

 Organisms have been found in a dog indistinguishable from 

 Trypanosoma herheruin, the active cause of debab, and the animal 

 presented all the usual symptoms of attack. Nearly all the camels of 

 the district suffer from myiasis and when on the march constantly 

 expel large whitish larvae from their nostrils. This is especially the 

 case in March and July, and these larvae are found in the frontal sinuses 

 and naso-pharyngeal cavities of every dromedary slaughtered, 30 or 

 more being quite a common number. Only two insects were bred from 

 a large number of larvae and these were sent to the Institute Pasteur 

 d'Algerie for identification. The harm done by these larvae to the 

 animals appears to be small and the natives believe that those 

 individuals which are free from them are intractable and difficult to 

 manage. At Beni-Ounif in the height of summer there was an out- 

 break of a species of Phlebotomus ; these midges were rare at Beni- 

 Abbes. 



Vida y costumes do berne. [The life and habits of Dermatobia hoyninis.] 



— Chacaras <& Quintaes, S. Paulo, xiii, no. 6, 15th June 1916, 



pp. 422-423, 4 figs. 



This is a popular article on Dermatobia hominis and refers to the 



mosquito, Janthinosoma lulzi, which is suspected of distributing the 



eggs of this fly. 



