COMMON FLIES AND HOW TO TELL THEM APART 147 



are nearly in a transverse row. The rounded tip of the body (fig. 25c) 

 shows, across the middle, faint traces of four low cones. The stigmal 

 plates (fig. 26) are scarcely elevated, black, less than their own diameter 

 apart, and each with three very short slits pointing towards those of the 

 opposite plate. 



This larva is common in decaying vegetable matter; and has been 

 reared from rotten apples, pears, squash, mushrooms and dead insect 



> « 



Fig. 25. — Larva of Muscina stabulam: a, Side view of head and prothorax; b, an- 

 terior or thoracic spiracles; c, side view of terminal segments of abdomen. 

 (Greene.) 



larvae. In one case a considerable number were passed by a child suf- 

 fering with summer complaint. Laboulbene records larvae of this species 

 vomited by a person suffering from bronchitis. 



Fig. 26. — Larva of Muscina atabulans: enlarged sketch of right stigmal plate. These 

 plates are less than their breadth apart. (Greene.) 



Calliphora erythrocephala Meigen 



The head of this larva is distinctly divided into two parts from above 

 (fig. 27, side view of head) ; each part or lobe has a tiny papilla. There 

 are two well separated mouth hooks. The anterior spiracles have from 

 nine to twelve lobes. Beginning with the third, each segment shows an 

 apical swollen ring or girdle, whose surface is scabrous (roughened like 

 a file) ; these rings are broader below than abovej and are here notched 

 on the posterior middle. Each ventral segment, beginning with the fifth, 

 is divided by a transverse groove near the middle. The anal area shows 

 a smooth median process, divided in the middle, and at each outer comer 

 is a cone. The stigmal field is rather concave, the upper lip with three 

 small tubercles on each side, the lower lip with two larger tubercles on 

 each side, and a median pair smaller and lower down. The stigmal 

 plates are about once and a fourth their diameter apart, each with three 



