INSECTS. 499 



of the different insects, a short description of its structure 

 will not be considered out of place. The ovipositor, borer, 

 or sting, generally consists of five 

 pieces : a pair of horny supports A 



(fig. 258) forming a sheath for v^ 



the borer or ovipositor, being 

 jointed at the point where they 

 issue from the cavity of the last 

 abdominal segment, and the 

 last joint is usually as long as 

 the borer itself. The latter con- Fig. m.- 

 sists of three bristles, of which the superior is chan- 

 nelled along its lower surface, for the reception of a pair 

 of finer bristles, and these are toothed at the point. The 

 three pieces, when fitted together, form a narrow tube, 

 through which the eggs pass to their destination, the 

 poisonous fluid also, which renders the sting of the Bee so 

 painful, is forced down the same into the wound. In the 

 Saw-fly, a part of this organ remains rudimentary, in other 

 respects it does not differ. 



The larvae of most of the Hymenoptera are footless 

 grubs, furnished with a soft head, and exhibiting but 

 little, if any, advance upon the maggots of the Diptera. 

 In the Saw-fly, however, the larva, instead of being, as 

 above described, a mere footless maggot, presents the 

 closest resemblance to the caterpillar of the Lepidoptera; 

 it is provided with a distinct horny head, and not only 

 with six thoracic legs, but in most cases, from twelve to 

 sixteen pro-legs are appended to the abdominal segments. 



The Saw-fly, fig. 255, most destructive to the gooseberry- 

 bush, is remarkable for the way in which the female pro- 

 vides for the safety of her eggs. This fly has a flat yellow 

 body, and four transparent wings, the outer two of which 

 are marked with brown on the edge. The female lays 

 her eggs on the under-side of the leaf, along the projecting 

 veins; these are so firmly attached, that they cannot be 

 removed without crushing. The instrument which the 

 little insect uses for the purpose of cutting the leaf, is the 

 most remarkable piece of perfect mechanism imaginable ; 

 securely lodged, when not in use, in a long narrow slit 

 beneath the abdomen, and protected by two horny plates, 



KK 2 



