133 



common along the Mbomu and also small midges, probably 

 Ceratopogon sp. Haematopota spp. are abundant in the open game 

 country ; Chrysops occurs, but is nowhere common. The rarity or 

 complete absence of Glossina in the areas most stricken by the disease 

 is remarkable. These flies are only known to the men who travel to 

 some distance from the locahty and are quite milaiown to the women 

 and children, who remain at home, and yet all are equally infected. 

 The disease is described as attacking one or more groups of huts at 

 a time, the population of the whole village being ultimately entirely 

 wiped out. The author says that it is quite clear that species of 

 Glossina are not responsible for these disasters and play no part in 

 the family contagion. The great marshy plains around Ali in the 

 »Sande country are in no sense good breeding places for tsetse, which 

 indeed are not to be found there. Mosquitos, however, swarm, and 

 the author is of opinion that, though the endemicity of the disease 

 may be dependent on Glossina, the epidemicity is due to mosquitos. 

 He cites the work of Heckenroth and Blanchard and of Roubaud and 

 Lafont on the transmissibihty of trypanosomes by Mansonia and 

 Stegomyia [see this Review, Ser. B, i, p. 191, and ii, p. 58] in support 

 of this view 



Hunter (W. D.). Some observations on Medical Entomology.— Proc. 



Entom. Sac. Washington, Baltimore, xvii, no. 2, June L915, 

 pp. 58-69. 



The blood -sucking habit of certain insects is the basis for the 

 transmission of the majority of insect-borne diseases. Among the 

 inter-relations which are probably concerned mth this is the habit of 

 certain parasites in man and other animals to swarm in the peripheral 

 blood during the time when nocturnal insects are active and the host 

 is least fitted to interfere with their attack. A consideration of 

 importance is what may be termed domesticity, especially in the case 

 of yellow fever, kala-azar and Chagas' disease. The closer the 

 association between any insect and man, the greater wnll be the 

 hkehhood of disease transmission, provided other necessary conditions 

 are fulfilled. Domesticity does not act as an important factor in 

 tsutsugamushi and spotted fever ; the former occurs in wild rodents 

 and reaches man through a mite, Trombidium akamushi, which attacks 

 him when he goes into the fields ; the spotted fever tick probably 

 acquires the virus of spotted fever from cei-tain wild animals. Another 

 class of diseases may be due to the accidental contact with the 

 pathogenic organism (instead of natural contact as in spotted fever), 

 or accidental contact with food. Cockroaches may in this way become 

 connected with tuberculosis or similar maladies. In some cases, as 

 in Oscinis sp., transmission may be by insects which become 

 contaminated by feeding upon or visiting the excreta of affected 

 individuals. The last class of cases consists of those in which insects 

 serve as intermediate hosts for Cestode or Nematode parasites ; the 

 larva of a Scarabaeid beetle acts as an intermediate host for 

 Echinorynchiis hirundinaceus, parasitic in pigs. The cysticercus stage 

 of Hymenolepsis diminuta, a Cestode parasitic in man, may be carried 

 by species of Pyralis, Anisolabis, Ascis and Scaurus. The most 



