XIV] 



LIFE-CYCLE 



229 



The larvae may be found in rotting logs and stumps, in the soil 

 at the edges of pools and streams, under stones in ditches, or 

 swimming free in the water. If kept supplied with a diet of 

 angle- worms the larvae can easily be reared, either in jars of 

 moist earth, or in jars containing sand and water. As a rule 

 they are cannibalistic in habit and only one can be reared in 

 each jar, but T. biguttalm is an exception to this rule, and in 

 this species several can be reared together in the same receptacle. 

 The larvae are cylindrical in form, pointed at both ends ; the 

 body is composed of eleven segments, each of which is usually 

 encircled by a prominent fleshy ring, or row of protuberances, 



Fig. 61. Egg-mass and mature larva of Tabanus kingi Austen, a, egg- 

 mass, x 6 ; b, lateral view of larva, x 3 ; c, lateral view of 4th and 5th 

 abdominal segments, x 6 ; d, posterior view of anal segment (inverted), 

 X6 ; e, lateral view of anal pseudopod. (After King.) 



which are most pronounced on the ventral side, where they serve 

 as prolegs. The head is small, but distinct, and the mouth parts 

 are very peculiar ; the mandibles are attached so as to move 

 antero-posteriorly ; when they are retracted the anterior ends 

 point forwards, but when extended they point downwards and 

 backwards, thus forming a pair of hooks that serve to hold prey. 

 The duration of the larval stage depends upon the temperature. 

 In temperate countries the larva usually lives through the 



