192 



THE LESSER HOUSE-FLY AND THE LATRIXE-FLY 



■ The spiny character of the flagelliform appendages and body 

 of the larva causes particles of dirt to adhere readily to the 

 bodies and appendages of the larvae. In consequence the larvae 

 have a very dirty appearance, and their external features are 

 almost hidden by the accumulated particles of dirt and filth 

 adhering to them. 



The larval period may extend over a week, or it may last for 

 three or four weeks if the substances in which the larvae are feeding 

 become rather dry. When fully groAvn it is covered fairly thickly 

 with dirt, w^hich is of great assistance in the formation of the pupal 

 case, as this is formed of the larval skin. 



Fig. 86. 



Fig. 84. 



Fig. 84. Fannia canicularis. Lateral aspect of cephalic region of larva; a.sp. anterior 

 spiracular process. 



Fig. 85. F. cxiniadarh. Palmate and sessile dorsal appendage of larva. 



Fig. 86. F. canicularis. Posterior spiracular process of larva. 



In changing into the pupa, the cephalic region is retracted 

 and the length of the larva is thereby decreased. The larval 

 skin, with its covering of dirt particles, forms the co-arctate 

 pupal case. Before pupating, the larva leaves the very moist 

 substance in which it may have been living and seeks a dryer 

 situation. The pupal period extends over a period of seven to 

 twenty-one days, or longer, and it is not unlikely that larvae, 

 which have developed very late in the season, pass the winter 

 in the pupal state, as is the case in certain other species of 

 Anthomyid flics. The adult fly emerges by pushing off the 

 anterior segments of the pupal case. 



