NOTES ON ANOPHELES IN CEYLON. 269 



presuming that the temperature is pretty uniform as it is at Trincomalie 

 at this time of the j r ear (March-May), namely 93° in the shade and 80° 

 at night, the time required would be not less than three weeks under 

 favourable circumstances. A rapid succession of broods is constantly 

 taking place during the active life of the imago, from January to June 

 at any rate, as is evidenced by the different growths of the larva? when 

 collected. 



The pupa of Anopheles fuliginosus can, I think, be scarcely distin- 

 guished from others of the genus ; it is extremely active when disturb- 

 ed, progressing by a rapid to and fro movement of its two caudal fins ; 

 as a rule it remains quiescent on the top of the water with the air tubes 

 just awash. On being disturbed it seeks refuge by diving to the 

 bottom tail first and hiding in the interstices of the water weed, but it is 

 unable to remain under water for any length of time and ascends again 

 by its own buoyancy. 



It remains in the pupa stage almost exactly twenty-four hours ; the 

 Anal change from the larva to the pupa takes place towards sunset, and 

 twenty-four hours afterwards the imago is produced. Invariably, the 

 imago is hatched out between the hours of 7 p.m. and midnight, 

 usually between 7 p.m. and 8 p.m., and takes place thus :— 



The back of the thorax at its apex becomes slightly tilted up for 

 some few minutes, the tail parts — which as a rule lie curled forwards 

 beneath the head — become extended, and this is the first obvious sign 

 that the final stage is about to take place. One or two violent con- 

 tractions and extensions of the tail cause the thorax to split down the 

 centre : there is then a momentary pause, after which the contents of the 

 thorax and abdomen shoot forward, causing the insect to rise suddenly 

 from its case and remain at a somewhat acute angle with the pupal 

 covering; the fore and middle legs being now extended, release the head 

 and palpi which were tucked up underneath the thorax. Immediately 

 the head is released, the insect shakes itself free from the pupa case 

 and crawls on to the surface of the water, if no other support be 

 near ; the wings are developed almost instantaneously, but are somewhat 

 limp and unavailable for flight until five minutes have elapsed ; the logs 

 are, however, stronger, and it is on them tl :;t the insect depends ia 

 the first instance. If the wings get wet, the insect is done for, as it 

 thus lies helpless on the water. The above performance takes rather 

 less than a minute for its completion. The ability of the insect to rest 

 on the surface of the water without injury is noteworthy, In colour the 



