INSECTS : STINGS AND OVIPOSITORS. 145 



A modification of tliis apparatus is found tlirougli« 

 out a very extensive order of insects, — the Uyinenop- 

 tera j but in the majority of cases it is not connected 

 with purposes of warfare. "Wlierever it occurs it is al- 

 ways confined to the female sex, or (as in the case of 

 some social insects) to the neuters, which ai"e undevel- 

 oped females. "When it is not accompanied by a poison- 

 reservoir it is ancillary to the deposition of the eggs, 

 and is hence called an ovi])Ositor^ though in many cases 

 it performs a part much more extensive than the mere 

 placing of the ova. 



In the large tribe of Cuckoo-flies {Ichneumonidoe)^ 

 which spend their Qgg and larva states in the living 

 bodies of other insects, this ovipositor is often of great 

 length ; even many times longer than the rest of their 

 bodies ; for the larvae which have to be pierced by it 

 require to be reached at the bottom of deep holes and 

 other recesses in which the providence of the parent 

 had placed them for security. The structure of the or- 

 gan may be seen in this little species, not more than 

 one-sixth of an inch in entire length, of which the ovi- 

 positor projects about a line. Under the microscope 

 you see that this projection consists of two black fleshy 

 filaments, rounded without and flattened on their inner 

 faces, which are placed together, — and of the true im- 

 plement for boring, in the form of a perfectly straight 

 awl, of a clear amber hue, very slender and brought to 

 an abrupt oblique point, where there are a few exceed- 

 ingly fine reverted teeth. It is probably double, though 

 it refuses to open under the pressure which I bring to 

 bear upon it. At the base are seen within the semi- 

 pellucid abdomen the slender horns, on which the mus- 

 cles act in projecting the borer. 

 7 



