146 SANITARY ENTOMOLOGY 



of minute granules, ending each side in a larger granulate tubercle ; there 

 are no tubercles outlining the stigmal field ; the stigmal plates are sub- 

 triangular, about one and one-half times their diameter apart, black, 

 and each with three pale areas containing an S-shaped slit (fig. 24). 

 These slits are never near each other like in the house fly, and there is no 

 apparent button. 



This larva commonly breeds in manure of various kinds, but also in 



Fig. 23. — Larva of Stomoxys calcitrans: enlarged sketch of thoracic spiracles. (Greene.) 



decaying matter, and is not often passed by people, but there is one 

 record. Horse manure, cow manure, and warm, decaying vegetation, like 

 old straw and grass heaps, are common breeding places. 



Fig. 24. — Larva of Stomoxys calcitrans: enlarged sketch of right stigmal plate. These 

 plates are one and one-half times their breadth apart. (Greene.) 



Muscina stabulans Fallen 



Head of larva (fig. 25) divided into two parts from above, no dis- 

 tinct papilla ; two great hooks close together ; anterior spiracles with 

 about six lobes (fig. 25b). The surface of the segments is mostly smooth. 

 Beginning with the fifth segment, on the under side, there is a basal, 

 transverse, swollen area, furnished on the crest with rows of teeth ; each 

 of tliese areas is divided on the median line. On the next to the last 

 segment there is a similar area at the tip, but not divided. The seg- 

 ments below also show a transverse line before the middle. The last 

 segment has the anal basal area with spines, but not very prominent, 

 and bears a median and three lateral tubercles with spines. The tubercles 



