429] LARVAE OF THE TENTHREDINOIDEA—YUASA 111 



the New York State Museum, labeled "a 2766" and "a 2261" were exam- 

 ined by me. 



Trachelus Jurine 



Antennae apparently with four segments — according to Gahan five 

 segments present; body thickest dorso-ventrad in meso thorax, second 

 and third abdominal segments widest, the ninth and tenth tapering 

 suddenly; suranal process rather short, tapering caudad gradually, chit- 

 inized dentiform tubercles wanting, with or without stiff short setae, 

 if setae present they do not arise from chitinized bases; ultimate tergum 

 setiferous on both sides of the median depression, convex as viewed from 

 side, truncate on the caudal aspect, not declivous caudad; third abdominal 

 segment with three annulets, annulet 2 largest and with a transverse row 

 of setae; subanal appendages peg-like, unsegmented. 



Trachelus tabidus Fabricius. — Suranal process without distinct con- 

 striction, with or without brownish setae, if present, setae arranged in a 

 irregular circle in the proximal half; subanal appendages brownish with 2 

 minute setae at the distal end, and with 1 or 2 setae which are separated 

 from the remainder of the setae on the sternum; lateral area of suranal 

 lobe with 5-7 setae; antennae with segment 4 bluntly rounded, segments 

 2 and 3 ring-like, segment 1 narrow but large in diameter with a seta on 

 the dorsal margin, segments all brown; bore in the stalks of wheat, rye, 

 and barley (Gahan 1920). 



Cephus Latreille 



Antennae apparently with four segments — according to Middle- 

 ton five segments present — segment 4 less than twice as long as wide; 

 abdominal segments 5-8 with ventral swellings corresponding in position 

 to larvapods; suranal process without chitinized dentiform tubercles, either 

 with a narrow ring-like distal chitinized portion and a semicircular row of 

 setae or with a long cylindrical distal portion and two or more irregular 

 rows of whorls of setae on the proximal portion, the distal margin of the 

 distal chitinous portion entire and smooth; subanal appendages papilla- 

 like, cylindrical, more than twice as long as wide, bluntly rounded at the 

 distal end, with one or more setae near the proximal end; lateral area of 

 suranal lobe with 7-15 setae; mandible with three dentes. 



According to Rohwer (1917) only two species of this genus are known 

 to occur in North America. They can be separated as follows: 



SPECIES OF CEPHUS 



Suranal process with the distal chitinized portion cylindrical, twice as long as wide, setae on 

 the proximal portion arranged in two or three irregular whorls; subanal appendages with 

 several setae; lateral area of suranal lobe with about 15 setae; the only true Nearctic 

 species known; bores in stalks of Elymus, Agropyron, Phleum, and wheat, cinctus Norton. 



