270 MEDICAL ENTOMOLOGY 



the mosquitoes should be liberated into a net fitted over a patient's 

 bed. One of the writers found that this was the only way to feed 

 Culex fatigans, which had been hatched from eggs, on Kala Azar 

 patients. This last method of feeding mosquitoes is, however, seldom 

 necessary. 



Mosquitoes can be fed on small birds, such as sparrows, canaries, 

 owls, and pigeons, by liberating them in large cages containing the 

 birds. Several strong wire supports should be fixed inside the cage 

 for the birds to rest on. A muslin bag is secured over the head of 

 the bird by tying it securely with two tapes under the wings ; this 

 prevents it from flying about in the cage. 



In all feeding experiments with mosquitoes which have for their 



object the investigation of the life history of some protozoon it is 



imperative to use bred insects. It has already been 



Pitfalls in feeding pomte( j out t h a t the early stages of certain flagellates of 



experiments ..... , 



the genera Hefpetcmotufs and Lntnidia occur in the 



alimentary tracts of mosquito larvae, so that breeding out the adults 

 from larvae is not a certain means of excluding these parasites ; spirochaetes 

 and certain microsporidia are also acquired by mosquitoes early in their 

 larval stages. In the past these parasites have been a fruitful source of 

 error, and there can be no doubt that they have been confused with 

 blood parasites which the mosquitoes may ingest. The only way to 

 exclude such parasites is to breed out the imagines from eggs, and to 

 take the precaution of keeping the larvae in water which does not 

 contain any encysted stages. The possibility of heriditary transmission 

 should not be forgotten. 



The methods employed in dissecting mosquitoes will be dealt with at 

 the end of Chapter IV. 



