200 



THE STABLE FLY, STOMOXYS CALCITRANS LINN. 



eggs deposited at one period was ninety-four, and that the maximum 

 number of eggs deposited by a single female may be placed at, at 

 least, six hundred and thirty-two. Bishopp found that two feedings 

 are usually necessary between the deposition of each lot of eggs. 



There are three larval stages and the larvae are creamy white 

 in colour and have a shiny translucent appearance ; the young 

 larvae are even more translucent. The adult larvae, which measure 

 about 11 mm., are rather similar to those of if. domestica, but they 

 can be distinguished by the character of the posterior spiracles. 

 These (fig. 90, J.) are wider apart than in M. domestica and are 

 triangular in shape with rounded corners; each of the corners 



Fig. 90. Posterior end of mature larva of S. calcitrans. 

 A Posterior spiracle of the same, enlarged. 



subtends a space in which a sinuous aperture lies. The centre of 

 the spiracle is occupied by a circular plate of chitin. The anterior 

 spiracular processes are five-lobed. 



The developmental stages, according to my own and the obser- 

 vations of those who have studied the life-history in temperate 

 and tropical climates, are as follows : egg stage, twenty hours to 

 four days ; larval stage, seven to thirty days ; pupal stage, five to 

 twenty days. The whole life-history, therefore, from the depo- 

 sition of the eggs to the emergence of the adults, may vary from 

 about thirteen days to seven or eight weeks. The longest time 

 which I observed in any of my experiments was a few days over 

 ten weeks (Oct. 4th to Dec. 15th). In temperate climates it 



