SAliCOPHAGID^. 19 



is also iirovidcd with tliese spinulcs, but not so abundantly. Ai'ound 

 the middle of each segment, from 4 on, there is a row of about 22 

 tubercles, mostly spiooth; on each side of the ventral line are three 

 of these on a slightl}^ swollen area, like that seen in the Sarcophaga 

 from Limburger cheese. On most of the ventral segments is a trans- 

 verse area in front and one behind the row of tubercles which does 

 not have the spinules, but is transversely striated. On the dorsum 

 the segments from 5 on appear to be divided into three transverse 

 })ortions, the middle one bearing the row of smooth tubercles. Anal 

 tubercles not very prominent, with a short, stout cone at each corner, 

 all spinulose. The stigmal pit is small, nearly egg-shaped, about 

 one and one-fourth times as long as broad; its upper lip with the 

 usual three cones each side, all short, the intermediate one very 

 small; the lower lip has also the usual two cones each side, small, and 

 a median pair still smaller, and remote from edge of lip. The stig- 

 mal plates and slits are as usual in the genus. 



Chrysomyia macellaria Fab. 

 (Plate IV, figs. 67, 68, 69, 71.) 



The head from above is distinctly bilobed; there are two distinct 

 mandibles; the anterior spiracles are very short, and contain only 

 7 lobes. The posterior upper part of segment 1 is swollen and spinu- 

 lose. Each of the following segments (except 2) has a basal, swollen 

 ring, armed with reclinate teeth , the teeth of the anterior row always 

 the larger. Beginning with segment 6 the ventral part of each ring is 

 much broadened and divided transversely by a narrow smooth space. 

 On segments 5 to 10 there is each side behind a fusiform swollen 

 area pressing against the swollen ring of the next segment ; this area 

 is also spinulose. The tip of the body shows on the dorsal part a 

 great cavity, in the bottom of which are the stigmal plates, each 

 with three straight slits, those of one subparallel to those of the 

 other; no button. Behind the cavity is a high, transverse, spinulose 

 crest; and the ventral part of tip shows a spinulose ai-ea bearing 

 two rather widely separated, prominent, smooth tubercles. The 

 dorsal edge of the tip shows four small conical tubercles. 



The "screw-worm", as the larva of this msect is called, occurs in 

 sores and wounds of domestic animals, and also in man. There are 

 various records of its presence in the ears and nose, or nasal cavities, 

 of people, from swelling near the nose, from a boil under the arm, 

 under the skin of a child, and in the navel of a child. It is there- 

 fore hardly a possible factor in internal myiasis, and most of such 

 recorded cases ])robably belonged to some species of Sarcophaga 

 whose larvii) are very similar in aj)pearance to those of the screw- 

 worm. 



