142 SANITARY ENTOMOLOGY 



The larva is divided into fourteen parts, of which eleven are distinct, 

 called segments, and the first segment is the head. The head appears to 

 be bilobed, or divided into two parts when viewed from above, and each 

 lobe bears a minute cylindrical tubercle or papilla (fig. 13). Below is 

 the mouth opening; at one side and above it is tlie pair of mandibles or 

 great hooks (fig. 13). The second segment or prothorax bears on each 

 side, in the full grown larvae, a short fan-shaped process called the an- 

 terior spiracle. The eleventh body segment which might be taken for the 

 last is often a fusion of the seventh to tenth abdominal segments. The 

 eighth abdominal segment can always be identified by the stigmal plates 



^hgmaf fiyd (conf^ain/ng ^osfen'or sh'^maf pldes) 



\ /inal f-uUrcU. Vzn-fraf fusiform area. Lahra/ fusiform area 



|s An^z rior SPirac/e. 



.s 



Fig. ]3. — Characters of a muscid fly larva. (Greene.) Segment 1 is the head; 2-4 

 are thoracic segments; 5-11 are abdominal. Segment 11 really contains the seventh 

 to tenth abdominal segments, the spiracles being on the eighth, the anus in the tenth. 



or lobes. The ninth and tenth are usually small and ventral and enclose 

 the anus. For further details see fig. 13. 



Table to Separate the Larvae (Maggots) 



I. Spiny larvae. 



1. A larva with the body flattened; down the middle of the back are 

 two rows of spines or processes, there are also two rows along 

 the under side and a single row of spines along each side. These 

 spines or processes are pointed and covered with many bristles. 

 There are also two stigmal plates on top of the last segment. 

 (Figs. 11^-16.) Fannia canicularis. 



9,. The larvae of Fannia scalaris are similar (figs. 17-19), but the 

 processes have fewer side branches. 



II. Smooth larvae. 



A. With one great mouth-hook ; slits in stigmal plate winding. 



1. Body broadly rounded at rear end, without spines. Stigmal plate 

 with three winding slits (figs. 20 to 22). Musca doinestica. 



