Proteosoma to Birds by the Mosquito. 445 



in net No. 1, and were caught in separate test-tubes which were then 

 plugged with wool and placed in the incubator. Of the control series 

 in net No. 2, where the non-infected birds had been placed, eighteen 

 were caught and treated in the same way. 



On the following two evenings, with minimum temperatures of 6O7 

 and 63'2, sixty-three and forty-six mosquitoes were fed on the in- 

 fected birds, net No. 1, and were kept for the preparation of speci- 

 mens; and twelve mosquitoes were fed on the non-infected birds, 

 net No. 2, bringing the number of the control series up to thirty-eight. 

 At a later date eighteen mosquitoes were fed on a blue jay with numerous 

 halteridia. 



On the third day the sixty-three mosquitoes, from net No. 1 (with 

 exception of those previously killed for examination or which had died) 

 were released inside a clean net free from other mosquitoes. Birds 

 free from Proteosoma were also placed in this net.* 



In the morning all mosquitoes found inside were collected. Most of 

 them had fed well. The minimum temperature during the night had 

 been 63-2 F. 



The mosquitoes were not fed on the following night as they were 

 full of blood which most of them voided during the night. Many died 

 next day. 



The remainder were given the opportunity of refeeding every night 

 after this ; but as a spell of cold weather set in with minimum tempera- 

 ture of 44 49 F. (only on one night did it exceed 50 F.) few fed 

 well or at all, and there was a consequent continued heavy mortality. 

 Only one insect, which subsequently escaped in the night, being alive 

 on the 10th day. 



This method of feeding was very unsatisfactory in exceptionally 

 cold weather. During the day the mosquitoes being kept warm in the 

 incubator rapidly digested their food, whilst at night the cold rendered 

 them torpid and they did not feed. 



The control mosquitoes, of net No. 2, were treated in exactly the 

 same manner, being fed on birds free from Proteosoma. The last died 

 on the 13th day. 



7. The results of the two series are as follows : 



Of sixty-three mosquitoes fed on proteosomal birds, forty-nine were 



* This is the method Boss employs to re-feed mosquitoes. If infected birds are 

 employed to re-feed the insects, a younger generation of coccidia is produced; I 

 therefore used sterile birds for this purpose. 



The method works fairly well in warm weather, but there is always some loss, as 

 the full number is never collected again in the morning. As the process is repeated 

 over and over again, this loss becomes serious, the more so the longer the period 

 required for maturation of the coccidia. Moreover, in a frequently repeated 

 process of this kind there is always the possibility of an outside mosquito getting 

 inside the net, and to that extent vitiating the experiment. 



