30 STUDIES IN INSECT LIFE, ETC. 



through the moist, semi-liquid surroundings. The 

 skin is usually moulted some twenty-four hours 

 after birth, but all these time-limits depend much 

 upon the temperature and favourable conditions. 

 With normally high temperatures say, with 

 86 to 95 F. the larva will become fully grown 

 in five or six days. The third and final stage, 

 after the second moult or ecdysis, lasts three 

 days, and when fully grown the maggots are 

 about half an inch in length. Externally, twelve 

 segments are visible, but the internal anatomy 

 shows that thirteen are really present, though 

 one is almost " masked." 



It is only during these larval stages that the 

 insect grows, and it is never more bulky than 

 in the third larval stage. Now it leaves the 

 moist situation in which it has flourished, and, 

 crawling through the manure, seeks some dry 

 or sheltered corner near the surface of the manure 

 heap. For a time it rests, and then after an 

 hour or two's quiescence it retracts its anterior 

 end and assumes a barrel-shaped outline, its 

 creamy white colour slowly changing to a mahog- 

 any brown. The larval skin forms the pupa- 

 case, and within this pupa-case the body of 

 the larva undergoes a wonderful change, far 



