BLACK GRAIN-STEM SAWFLY. 7 



such grasses as Elymus, Bromus, Agropyron, and in fact any of the 

 cultivated or wild grasses whose seasonal development is such as to 

 provide a succulent stem of sufficient size to accommodate the larvse 

 during the period of larval activity, May and June, should be viewed 

 with suspicion. 



SYNONYMY AND DESCRIPTION OF TRACHELUS TABIDUS. 



Since the original description by Fabricius (1), the name has 

 undergone a number of generic transfers, and it has been redescribed 

 or referred to under several specific names. 



It is the opinion of the writer, however, that some of the pub- 

 lished synonymy is incorrect. Trachelus haemorroidalis Jurine (17) 

 is listed as a synonym by Dalla Torre (38). The figure given by 

 Jurine is not that of tabidus, but is undoubtedly identical with 

 Cephus emails Klug (12). The latter name is generally recognized 

 by European writers as a synonym of haemorrhoidalis Fabricius (2). 

 Konow (41) includes Sirex macilentus Fabricius (9), Cephus erberi 

 Damianitsch (30), and Cephus vittatus Costa (32) as color varie- 

 ties of tabidus. The large number of specimens of tabidus examined 

 by the writer show no variation in color comparable to macilentus 

 as illustrated by Coquebert (10), and since other European writers 

 generally have recognized this as a distinct species it has been ex- 

 cluded from the synonymy. Cephus erheri is described as having 

 the third to seventh dorsal abdominal segments banded with yellow, 

 the band on the third segment interrupted, while the third to ninth 

 ventral segments are said to be margined with yellow laterally. In 

 no specimen of tabidus examined' by the writer is there any indica- 

 tion of a dorsal band of yellow on the abdomen nor are the ventral 

 segments margined with yellow. Like macilentus, this species is 

 therefore excluded from the synonymy. The description of vittatus, 

 on the other hand, agrees closely with tdbidus, and there seems to be 

 no good reason why it should not be considered a pure synonym in- 

 stead of a color variety. 



Following is the complete synonymy of Traclielus tabidus as 

 understood by the writer: 



Traclielus tdbidus (Fabricius) Jurine. 



Sirex tabidus Fabricius (1), (2), (4). — Villers (5). — Linng (6). — Christ 

 (8). — Fabricius (9). — Coquebert (10). — Walckenaer (11). — Rossi 

 (19).— Herrich-Schaffer (26).— Dumeril (29). 



Tenthredo longicollis Fourcroy (3). — Villers (5). 



Astatus tabidus Klug (12).' — Panzer (15). 



Cephus tabidus Fabricius (13). — Latreille (14). — Panzer (16). — Latreille 

 (18).— Lepeletier (20).— Stephens (23).— Hartig (24).— Blanchard 

 (25).— Lucas (27).— Costa (28).— Taschenberg (31).— Andre (33).— 

 Cameron (34), (35).— Magretti (36).— Costa (37).— Dalla Torre (38). 



