204 TJ^^ Philippine Journal of Science ms 



live angleworm was placed in the glass dish while the resting 

 larvse were observed with a lens. The worm was not placed 

 in the immediate vicinity of the mass of larvse, but nearly 4 

 centimeters distant. The presence of the food appeared to act 

 as a stimulus. No movement was made toward the worm, but 

 each larva appeared to become greatly excited and began to 

 prod the larva nearest to it and to nip its neighbor's appendages ; 

 several very marked instances of laceration were noted. This 

 doubtlessly marked the beginning of systematic cannibalism. 

 From this cause, 39 of the 265 larvae kept in a large glass 

 dish were destroyed within four days. Four dead bodies were 

 recovered. Upon another occasion the extent of cannibalism was 

 very much more marked. A lot of 415 larvse which hatched 

 on November 12, 1912, was placed in a deep glass dish with 

 moist lake-beach sand, and fed daily on angleworms. Each 

 morning it was observed that only about one-half of the worms 

 supplied the previous day was eaten, so that with the daily 

 fresh supply more than enough food was present. Another 

 lot of 300 larvse, the same age as the preceding, was kept in 

 individual glasses under similar conditions. On December 6, 

 counts were made of the survivors in the large glass dish. 

 Thirty-five larvse remained, of which 18 were the maximum 

 size, 11 were a little more than one-half this size but equal 

 to the largest found in the individual jars, and the remaining 6 

 larvse were so small as to be easily overlooked. The census 

 taken of the larvse from the individual jars showed a loss 

 of 12, or less than 5 per cent. Allowing 5 per cent for loss 

 from other causes, it appeared that above 85 per cent of the 

 larvse kept together in the large jar was destroyed through 

 cannibalism. 



It has been observed by Hine in other species that a Tabanus 

 larva is enabled to survive for a few days in the absence of 

 food. In this species likewise there seems to be a decided 

 resistance to starvation, two instances showing periods of ten 

 and twelve days. 



The movements of the body are in general similar to those 

 of larvse of the muscid type. There is a general progressive 

 peristaltic movement, invariably accompanied by a decided 

 telescoping of the segments. The head is raised as the prolegs 

 of the anal end push the body forward, then it is lowered. 

 The mouth is projected when the head capsule is extended, 

 but recedes quickly when the glass sides of the container or 

 any obstacle is encountered. The larva can easily move back- 

 ward for a considerable distance. This it does if wedged in a 



