6 JAMES WATERSTON. 



sheltering in spots defended by the Hydropterid plant, Salvinia natans. Along the 

 west side of Amatovo, sinensis was very plentiful, its presence depending on patches 

 of Spirogyra in the shallows. 



Observations were made to ascertain whether, and if so at what time, the larvae 

 would die out with the approach of colder weather. By the 31st October they had 

 practically vanished from below Galavanci, while from the 20th onwards it was 

 difficult to get many at Vardino. On 1st Nov. only a few examples could be found 

 in these localities. During the week in which this diminution in the numbers of 

 sinensis was observed my visit to the lakes had been paid between 2 and 4 o'clock 



Fig. 1 . Inner basal lateral lobes of the male genital armature of Anopheles 

 sinensis (top), A. maculipennis (left), and A. palestinensis (right). 



in the afternoon. Returning on the forenoon of 2nd Nov. to Amatovo during a 

 spell of bright sunshine we found the larvae quite numerous ; the inference being, 

 I think, not that the stock had up to then been seriously depleted, but merely that 

 the daily period of larval activity had been shortened. The examples so collected 

 showed no signs of hibernating when brought down to the Laboratory, but fed up 

 and pupated a little more slowly than others from the same site taken a fortnight 

 earlier. The last imagines from this batch emerged during the first week in December. 

 Probably hatching out under natural conditions stopped at least a fortnight earlier, 

 for during that time the weather was extremely cold and the Laboratory was heated. 



