HYMENOPTERA. 211 



stripes on the back, that in the middle bluish and those on the 



sides yellowish*. 

 Those species, in which the antennae present but three very distinct 

 joints, the last of which forms an elongated, prismatic, or cylindrical 

 club, more slender, ciliated, and sometimes forked in the males; and 

 where the two costal nervures of the superior wings are very remote 

 from each other, constitute the subgenus 



Hylotoma, Lat. Fab. — Cryptus, Jur. 



Some — ScHYZocERA, Lat.; Cryptus, Leach, Lepel. — have four cu- 

 bical cells, and the antennae forked in the males. The middle of the 

 tibiae is destitute of spines f. 



Others — Hylotoma properly so called— similar to the preceding in 

 their wings, have their antennae terminated in both sexes by a simple 

 or undivided joint. Most of them — Ht/lotomes, Lepel. — have a spine 

 in the middle of the four posterior tibia;. The larvae or pseudo-cater- 

 pillars have from eighteen to twenty feet. 



H. roscE; Tenthredo rosce, L. ; Roes., Insect., H, Vesp., IL 

 Four lines in length ; head, top of the thorax, and exterior mar- 

 gin of the superior wings, black; remainder of the body saffron- 

 yellow ; tarsi aunulatcd with black. 



The larva is yellow, dotted with black ; it gnaws the leaves of 

 the Rose-tree. 

 M. Lepeletier re-unites to the Cryptus, Leach, certain species which 

 only differ from the preceding ones in the absence of spines on the 

 middle of the four posterior tibise. 



Other Hylotomcp, distinguished by the same negative character, 

 but which have but three cubital cells, form his genus PtUia X. 



Sometimes the antennae have at least nine very distinct joints, and 

 do not terminate suddenly in a club. 



In some, and the greater number, the antennee, always simple in 

 both sexes, or at least in the females, have fourteen joints at most, 

 and commonly but nine. 



Tenthredo, Lat. Fab., 



Or Tenthredo proper, where the antennae consist of nine simple 

 joints in both sexes. 



The larvse have from eighteen to twenty-two feet. 



The number of dentations in the mandibles of the perfect Insect 

 varies from two to four. The superior wings also differ in the num- 

 ber of their radial and cubital cells. These characters have been 



* For the other species, see Oliv., Encyc. Method., article Ci'miea;; Fab.; Lat., 



Gen. Cnist. et Insect., Ill, p. 227 ; Jurine, genus Tenthredo; Panz., Hymen. ; and 



the works already quoted. 



t Leach, Zool. Miscell., Ill, p. 124 ; Lepel., Monog., Tenthred., p. 52. "' 



X Lepel., lb., p. 49. For the other species of Hylotom.T, see the same work, the 



preceding one of Dr. Leach, and the Monograph of the various genera of this family 



by Klug. 



