198 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



species of Anopheles have not been looked upon as particularly- 

 associated with man. However this is only due to the fact that the 

 habits of the Anopheles have not been properly understood and par- 

 ticularly to the failure to differentiate the habits of the different species. 

 There is every indication that those species which transmit malaria 

 thrive in the vicinity of man, while, on the other hand, those species 

 which live apart from man and do not habitually seek his blood are 

 inoffensive. That the habits of the different species of Anopheles 

 differ widely and are in direct relation to their effectiveness as trans- 

 mitters of|malaria is brought out in an interesting manner in the 

 paper by Mr. Jennings on mosquito control in the Panama Canal 

 Zone (printed on the preceding pages of this number). Conversation 

 with him has added further data that support this view. Investi- 

 gation of the role of the different species in the transmission of malaria, 

 by inducing them to bite malaria carriers, has shown that Anopheles 

 albimanus, the species which thrives particularly about settlements 

 and is most persistent in entering houses and obtaining blood, is the 

 principal factor in malaria transmission — no less than 70 per cent of 

 this species developing the parasites.^ An interesting point, brought 

 out in conversation with Mr. Jennings, is that this species appears 

 to be absent from those parts of the upper ,Chagres River which are 

 uninhabited. It is highly probable that the reason for the absence of 

 Anopheles albimanus from such localities is that this mosquito not 

 only prefers, but probably needs, human blood. It has been suggested 

 that the absence of albimanus from the upper Chagres was due wholly 

 to the absence of suitable breeding-places. It appears, however, that 

 this objection is not valid. Both Mr. Jennings and Mr. Busck have 

 explored the Chagres for mosquitoes and they assure me that there 

 are abundant opportunities for A. albimanus to breed. Neither of 

 them found albimanus and they could hardly have failed to do so had 

 it been present.^ 



The observations of James and Liston on the habits of the Anopheles 

 of India show that the species of that country likewise differ in habits. 



1 Darling, i^amuel T., Studies in relation to malaria, Washington, Govt. Printing 

 Office, 1910. 



2 Since writing the above I have come upon a record of observations on Aiiopheles 

 tarsimaculatn, a geographic race of albimanus, by the Rev. James Aiken of Berbice, 

 British Guiana, which support my contention. Under the name Cellia albipes he 

 indicates the relation of this species to man as follows: " It is to be noted that on 

 the Canje creek further up than Baracara I found no Anophelina, the same remark 

 applies to the Berbice River above Mara, and in a collection made by Mr. Beckett 

 at Sandhills none appeared. On a visit to the Supenaam creek I was also unsuccess- 

 ful in finding this mosquito. All these districts are very sparsely populated, and so 

 far as our observations go they are only to be found near human dwellings." — 

 (British Guiana Medical Annual for 1906, Domerara, 1907, p. 66.) 



