WOOD-BORERS. 105 



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genera have nine-jointed antennae, but in some of the less typical 

 sub-families, such as the Lophyrincc and Lydinm, the number of 

 joints is frequently much greater, often exceeding twenty. 



Family TI. — Siricidce. 



Ovipositor of the female exserted, and forming a powerful awl 

 for piercing the bark of trees, in the solid wood of which the 

 larvae feed. 



The number of known species of this family is not large. The 

 insects themselves are, however, large and conspicuous, and are 

 not very uncommon in fir plantations, though much more abundant 

 on the Continent than in England. The larvae sometimes remain 

 concealed in timber for years, and the flies, when arrived at 

 maturity, have been known to issue unexpectedly from the floor- 

 ing, or other timber of a house, greatly to the consternation of the 

 inhabitants. Wood-feeding insects often vary very much in size, 

 and these are no exception to the rule, some specimens being almost 

 twice as large as others ; but they generally measure considerably 

 over an inch both in length and expanse. The two commonest 

 species are Sirex Gigas, Linn., and S. Nodilio, Fabr. In both 

 species the antenna are filiform, and many-jointed, and the 

 abdomen of the male is triangular at the tip, while that of the 

 female is provided with a long ovipositor, S. Gigas is yellow, 

 with two black bands on the abdomen in the female, and the tip 

 black in the male. S. Nodilio is of a purplish-blue colour. 



IT. — Hymenoptera Terebrantia — Entomophaga. 



Abdomen petiolated, or at least attached to the thorax only by 

 a small portion of its base ; larva footless ; parasitic on the eggs or 

 larvae of other insects, except in the gall-producing Cynipidce. 



Many authors make two subdivisions in this section : Pujnvora 

 or Spiculifera, including the families Cynipidce, ChalcididcB, Prodo- 

 trypidcB, Braconidce, Ichneumonidce, and Evaniidce ; and Tuhulifera, 

 including the Chrysididce. The latter family, however, appears to 

 me to belong rather to the Hymenoptera Aculeata than to the 

 Terehran'ia. 



Family I. — Cynipidce. 

 Ovipositor concealed, sub-spiral ; antennae straight, thirteen- 

 to fifteen-jointed ; wings with few veins ; either gall-producers or 

 parasites. 



