Abt. 1. NOETH AMERICAN SAWFLIES ROHWER. 13 



long been correctly recognized and is one of the few well-lniown 

 genera of the Tenthredinidae which does not have a synonym. In 

 the larva and in the adult the genus Cladius is closely allied to 

 PHophorus. 



The genus is distributed throughout the Palearctic Eegion. One 

 species has been described from the northern Oriental Region and 

 there is one species in the Nearctic Region. The fossil Cladius re- 

 cently described by Professor Cockerell should probably be referred 

 to Priophorus (p. 36). From our present knowledge it is fair to 

 assume that the genus Cladius originated in and is naturally confined 

 to the Palearctic Region. The North American species will prob- 

 ably be found to be an European form and the species from northern 

 India be found to occur onl}^ in that portion which is Palearctic. 



Generic Characters^ Adults. — Clypeus arcuately emarginate; an- 

 tennal foveae deep, large, extending almost to the eyes; supraclypeal 

 area strongly convex, rectangular in outline; inner margin of the 

 eyes slightly converging below ; anterior basitarsus subequal or longer 

 than the three following joints (fig. 3) ; the male antenna with 

 joints 3, 4, 5, and 6 with apical dorsal projections and with the third 

 joint with a strong basal projection beneath; the :intcnna of the 

 female short, the third joint compressed, distinctly concave be- 

 neath; radiellan cell with a distinct appendage; cerci long and 

 slender; lower margin of lancet strongly curved and armed with 

 eight large teeth ; the posterior margin of the lancet plates strongly 

 armed. 



Larvae. — See characters in above key. Larvae of only one species 

 available for stud3\ and all characters for genus are taken from this 

 species. 



CLADIUS ISOMERUS Norton. 



Figures 3, 7, 16, 17, 28, 2,9, 39, 45, 50, 60, 62-70, 72. 



Tenthredo (Cladius) isomera Harris, Cat. Ins. Mass., 1835, p. 5S3, without 



description. 

 Cladius isomera Norton, Proc. Bost. Soc. Nat. Hist., vol. 8, 1S61. p. 228; 



Trans. Amer. Ent. Soc, vol. 1, p. 74. — Murtfeldt, U. S D. A. Div. 



Ent. Bull. 22, 1890, p. 78. 

 Cladius pectinicornis Riley, Ins. Life, vol. 5, 1892, pp. 6-11, figs. 1 and 2. — 



Dyak, Can. Ent.. vol. 27, 1895, p. 340; Can. Ent., vol. 28, 1890, p. 239.— 



Dalla Torre, Catalogus Hymenopterorum, pt. 1, 1894, p. 291. — Marlatt, 



U. S. D. A. Tecbn. Ser. 3, Bur. Ent., 1896, p. 19.— Chittenden, U. S. D. A. 



Bur. Ent. Circ. 105, 1908, pp. 6-9, figs. 3 and 4. 



The location of the type of isomerus Norton is not definitely 

 known, but it is presumed that the female bearing number 185 in 

 the Harris collection is one of the tj'pes ; all others are probably lost. 



In 1892 Riley synonymized the American bristly rose slug 

 {isomerus) with the common European species {pectinicornis) and 



