16 STRUCTUEE OF CERTAIN DIPTEROUS LARV^. 



but are subparallel to them. Moreover, the stigmal field is strongly 

 depressed to form a deep stigmal pit, at the bottom of which are 

 situated the stigmal plates. The segments of the body bear complete 

 rings of spinose areas, and often supplementary pads on the sides. 



Sarcoi)haga larvae prefer animal matter, and have been found in 

 cheese, oleomargarine, pickled herring, dead insects, and human 

 feces. 



Sarcophaga incerta Walk. 



(Plate IV, fig. 75.) 



Body mostly scabrous, each little wrinkle or stria giving rise to a 

 very short, appressed, stout, spinelike bristle. Head deeply bilobed, 

 each lobe tipped with a very short papilla; mandibles two, well 

 separated. About seven lobes in the anterior spiracle. The basal 

 two-thirds of segments 3 and 4 is scabrous; beginning with segment 

 5 there is a scabrous fusiform pad each side, and the ventral area of 

 the scabrous basal ring is much broadened and transversely divided 

 by a furrow. Behind this is another longer transverse furrow rather 

 beliind the middle of the segment. The dorsum of these segments 

 shows four transverse areas, the posterior one rather broader than 

 the others. The last segment is short, scabrous; the anal area not 

 very prominent, scabrous, and with a small conical tubercle at each 

 outer corner. Stigmal pit about one and one-half times as long as 

 broad, its upper hp with three large, scabrous tubercles each side, the 

 intermediate one rather smaller than the others, the lower hp with 

 two large tubercles, and a median pair of smaller ones slightly back 

 from the margin. Stigmal plates about one-half their diameter apart, 

 each with three slits, subparallel to those in the opposite plate; no 

 button. 



Sarcophagid A. 



(Plate IV, figs. 73, 74, 78.) 



Body broad and rather flattened. Head small, bilobed, and a 

 minute antenna on each lobe; two well-separated mandibles. Apex 

 of second segment roughened ; the anterior spiracles hemispherical, 

 and occupying a depression at base of the second segment, provided 

 with a number of small tubercles; third segment at base \^"ith swollen 

 ring, showing striae and punctures ; surface of the following segments 

 minutely, transversely striate and punctate. Each segment trans- 

 versely divided, both above and below, into three regions, as shown 

 in the figures ; all more or less swollen, and a swollen area on each side ; 

 last segment striate and punctate as other segment; anal area hardly 

 prominent, with a rounded spinulose tubercle at each upper corner; 

 stigmal pit one and one-half times broader than long, rather deep, its 

 lips each with three minute cones or tubercles each side; the stigmal 



