THE XYLOPHAGA. 231 



preceding in the mode in which the abdomen is 

 attached to the thorax*, but differs from it in the 

 structure of the ovipositor, as also in the wood-loving 

 habits of the larvae, from which the name of XYLO- 

 PHAGA is given to the tribe. 



The ovipositor, in fact, presents exactly the struc- 

 ture which has already been described as the normal 

 form prevailing throughout the majority of the Hy- 

 menoptera, consisting of a stout horny piece, chan- 

 neled beneath for the reception of a pair of horny 

 bristles of the same length, but capable of moving 

 independently of their sheath, and leaving in the 

 centre a narrow canal through which the egg passes 

 to its destination. All the pieces of the true ovi- 

 positor are more or less toothed or serrated exter- 

 nally; they are enclosed, like the two saws of the 

 Phyllophaga, between a pair of two-jointed valves, 

 and, like these, occupy a long cleft of the last segment 

 of the abdomen, which, from its peculiar construction, 

 reaches nearly to the middle of the belly ; but they 

 constitute a far more powerful organ than that pos- 

 sessed by the Saw-flies, for they project considerably 



* These two tribes may be considered as forming a section or 

 suborder of the Hymenoptera, distinguished by the name of the 

 Securifera, and characterized by the attachment of the abdomen 

 to the thorax by its whole width, and by the structure of the 

 larvae, which are always furnished with a distinct horny head, 

 and with at least six legs. The remainder of the order, consist- 

 ing of the species in which the abdomen is attached by a narrow 

 stalk, and the larvae are footless grubs or maggots, may be called 

 the Petiolata, and may be subdivided into two groups, according 

 as the females are or are not furnished with a venomous sting. 

 This mode of division appears to me more philosophical than 

 dividing the order into those with, and those without a sting, 

 which has generally been followed by entomologists. 



