26 STRUCTUltJ': OF CEKTAIN DIPTEROUS LAEV^. 



These forms infest overripe fruit, and since such fruit is apt to 

 cause sickness, these hirvse are frequently reported bv physicians. 



Muscina sialmJaim Fall. 

 (Plato II, ligs. 17, 18, 19, 27, 28, 36.) 



Head hilobed from above, no distinct antenna?; two closely ap- 

 proximate mandibles; anterior spiracles of about six lobes. Surface 

 of segments mostl}" smooth; beginning with fifth segment there is on 

 the venter a long, basal, transverse, fusiform sw^ollen area, fur- 

 nished on the crest with rows of teeth; eacli of these areas is divided 

 on the median hue. On the penultimate segment there is a similar 

 area at tip, but not divided; the segments below also show a trans- 

 verse line before the middle. The last segment has the anal basal 

 area spinulose, but not very prominent, and with a median and three 

 lateral spinulose tubercles in a nearly transverse row; the rounded 

 tip of the segment shows, across the middle, faint traces of four low 

 cones. The stigmal ])lates are scarcely elevated, black, less than their 

 diameter apart, and each wdtli three very short slits pointing toward 

 those of the opposite plate. 



The larva of this species is common in decaying vegetable matter; 

 and it has been reared from rotten apples, pears, squash, mushrooms, 

 and dead insect larvae. In one case a considerable number was 

 l)assed by a child suffering from summer complaint. 



Laboulbene records larva? of this species vomited by a person suffer- 

 ing from bronchitis. 



Musc'uui assimilis Fall. 

 (Plate II, fig8. 20-22.) 



Head bilobed, each lobe with a prominent papiha; mandibles tW'O, 

 well-separated. Anterior spiracles with about nine lobes. Surface 

 smooth; the rings or girdles to segments distinctly outlined, but 

 little swollen; they are faintly scabrous, and on the ventral surface 

 broadened and transversely divided by a furrow; there is also on 

 most of the ventral segments a short, median, transverse line; the 

 anal area appears extruded as a broad, rather flattened lobe, tra- 

 versed by median and transverse grooves; the tubercle above has a 

 small cone at each outer corner. The stigmal field is margined on 

 each upper side by three very small conical tubercles, and behind b,y a 

 transverse row of four large conical tubercles close together, and 

 laterad of them is a minute tubercle. The stigmal plates are rather 

 niore than their diameter apart, and each sliow^s three short, straight 

 sUts dii-ected toward those of the opposite plate; the button is 

 distinct. 



Larvae in roots of a melon vine. 



