4 PROCEEDINGS OF THE NATIONAL MUSEUM vol.70 



10. Spiracular plate quite large as in figure 16; puparium with two small 

 bristles in the middle of the thoracic dorsum. 



(No. 16) Chrysopila foeda Loew. 

 Spiracular plate smaller, of medium size, as in figure 17 ; puparium with 

 four small bristles in the middle of the thoracic dorsum. 



(No. IT) Chrysopila ornata Say. 



DESCRIPTIONS OF SPECIES 



XYLOMYIA PALLIPES Loew 



Plate 1 



Habits. — Larvae are usually scavengers and may occasionally be 

 predacious. They have been found under the bark of fallen cotton- 

 wood trees {Pofulus) and also under the bark, and in the ferment- 

 ing sap in wounds, of tulip poplar {Liriodendron) . 



Larva {fig. 1). — Small; dull, dark yellowish brown; head pointed; 

 body transversely elliptical; sides parallel; 11 segments, in addition 

 to the head, of nearly equal length ; the last segment slightly longer 

 and rounded apically; surface of body reticulate except for a large 

 bare area on the dorsum of the first segment and a smaller area on 

 the second ; dorsal anterior surface of head terminates anteriorly into 

 a sharp process; on the side of the head, below the apex, is the 

 minute two-jointed thimble like antenna with the apical joint much 

 smaller ; near the basal outer angle of head is a small yellow bristle ; 

 near each dorso-anterior angle of segments 2 to 10 is a depression; 

 segments 4 to 11 have a transverse, anterior row of small, round 

 depressions, those of the last segment are larger ; segment 1 has tAvo 

 bristles at each anterior corner ; segments from 1 to 10 have a dorsal 

 pair of bristles just back of the transverse middle line and the seg- 

 ments from 2 to 11 have one lateral bristle; at each posterior angle 

 of the last segment is a small bristle; on the venter, all segments 

 except the last have a pair of widely separated bristles; along the 

 ventral segmental line of the last segment are four bristles, the two 

 middle ones the smaller; just back of the middle is a transverse row 

 of four bristles, between this row and the apex of the segment are 

 two bristles ; anal opening surrounded by a rounded ridge. Anterior 

 spiracle (fig. a) on the side of the first segment; it is heavily chitin- 

 ized, dark yellowish red, the anterior end much darker ; the narrow, 

 distinctly elevated ridges are pale yellow. The posterior end of the 

 larva opens transversely like a mouth, and within the lips, which are 

 yellowish brown chitinized, smooth and shining, is a central de- 

 pressed plate with a rounded ridge around the edge; in the middle 

 of this plate is a rounded elongate elevation with six small, rounded 

 punctures on each side, in the upper part are two transverse rows of 

 small, rounded punctures and at each of its lower corners are situated 



