280 W. A. LAMBORN. 



The attack of another Lispci in a similar way on a mosquito pupa was witnessed 

 on the same occasion. The pupa impaled on the fly's proboscis, was drawn from the 

 water, fully extended, to a little bit of leaf on which the fly had been sitting. It 

 was not seen to move, so that one is unable to assert that it was living when seized 

 by the fly. 



At a later date many instances were witnessed of attacks by the flies on mos- 

 quitos which had been unable to fly away on the previous night owing to the failure 

 of their wings to expand properly. One fly had impaled in the usual way a helpless 

 mosquito, and had dragged it on to a small stick in the water. On an attempt 

 being made to secure it, the insect flew across the water bearing its prey to another 

 support, a foot further off in the water. Threatened by another attempt it flew 

 up bearing its prey and settled fully another foot away on a blade of grass w^here 

 both were captured. Its prey, a female mosquito, moved freely after capture. 

 The manoeuvres of another fly were precisely the same when it was menaced with 

 the net. In view of the unsuspicious attitude of most of the flies previously cap- 

 tured, this wariness was a little surprising, more especially as they were taken, 

 with the water still in the shade, at an early hour when most insects of diurnal 

 habits are prone to be sluggish in their perceptive faculties. 



The pressure of other work made it impossible to study the behaviour of at least 

 four other Diptera, all having business on the water. One species appeared 

 to act as a scavenger, endeavouring to extract nourishment out of empty pupa- 

 cases and larval skins of mosquitos. Another small species, which was not captured, 

 was almost certainly predaceous on mosquito larvae. It gave from time to time 

 most careful and deliberate attention to the cleaning of its long, pointed proboscis, 

 after which it gradually stalked the smaller mosquito larvae breathing at the surface 

 film, endeavouring, seemingly, to thrust its proboscis into their air-tubes, and 

 repeating this action again and again, though in no instance was a successful issue 

 witnessed. 



In the same pool in which these Culex larvae occurred in swarms were a few 

 predaceous larvae of a much larger species of mosquito, which every now and again 

 attempted to secure one of the Cidex larvae, causing them instantly to scatter. 

 On the far side of the pool, which was about two feet across, was noticed a " rat- 

 tailed " larva struggling on the surface, and on near approach it was seen that one 

 of the larger species of mosquito larvae, almost fully grown, had seized it firmly 

 at the point of junction of the " tail " with the body. The rat-tailed larva wriggled 

 and contorted itseK in every possible way ; its tail became twisted round the 

 head of its adversary at least twice ; and it endeavoured to escape by diving into 

 the depths of the pool, but unsuccessfully. The mosquito larva never slackened 

 hold and, when its \dctim approached the surface, immediately put up its respiratory 

 siphon and probably nibbled away constantly, for by and by a portion of the cuticle 

 of the larva was seen to be partly detached near the mouth of its assailant and 

 to be trailing the water. Towards the end of a prolonged and desperate struggle 

 a second similar mosquito larva joined in the attack, seizing the Syrphid larva at 

 a point midway between the two extremities of its body. The Syrphid struggled 

 still more violently. Its new assailant, better situated for attack at a vital spot 



