16 THE OVIPOSITOR. 



built ovipositor. In that case it occupies the apical 

 half of the abdomen. 



The ovipositor proper consists of a pair of flattened, 

 broad, lancet-like organs, generally somewhat curved 

 towards the apex, and of a firm horny consistency. 

 Bach pair is composed of two distinct parts, viz. a 

 back piece or support (PI. X, fig. 5 a), and the 

 cutting instrument proper. The support is, as a 

 rule, very much stouter in texture than the "saw' : 

 itself. It is slightly hollow on one side, while on the 

 lower edge there is a thickened rim, by means of 

 which the " saw " is attached to it. At the base it 

 is much thicker than at the apex, while the colour 

 there is darker. On the surface of the support, as it 

 may be called, are not unfrequently a number of 

 transverse bars, readily noticeable by their deeper 

 colour. With most species these transverse bars are 

 simple, but occasionally they are armed with minute 

 teeth, e.g. Hylotoma, Nematus luteus. The support may 

 be (and this is more often the case) of the same shape 

 as the saw, but may be different, as in, e.g. Gintbex. 



The lower edge of the saw bears projecting teeth, 

 which may be simple projections somewhat like the 

 teeth of a hand saw, or these projections may them- 

 selves be armed with minute teeth-like indentations. 

 In Cimbex the edge is provided with little bead-like 

 projections, arising at the base from a pedicle, and 

 covered all over with minute teeth. Like the support, 

 the saw bears a number of transverse bars, distin- 

 guishable by their darker colour, and either un- 

 armed or minutely toothed (Cladius). Thus, the 

 saw (to quote Newport's illustration) is, in its most 

 advanced state, a lance, a saw, and file all in one, for 

 there is no doubt that the teeth on the bars serve as a 

 file. The structure of the saw and its support has a 

 direct relation to the work they have to do. Thus, 

 those species which deposit their eggs in twigs or 

 young branches have the ovipositor very stout, broad, 

 and well armed with teeth, e.g. Hemichroa rufa, 



