100 INJURIOUS AND USEFUL INSECTS 



the complex network of wing-veins with a multitude of small 

 cells, which is characteristic of Neuroptera, we may safely 

 refer it to the Hymenoptera. The abdomen is sessile, nearly 

 cylindrical in the female, a little flattened from above down- 

 wards in the male, and ends in a stiff, pointed horn, which 

 continues the line of the body. The trochanter (2nd joint 

 of the leg) is double, a feature which reappears in the 

 parasitic Hymenoptera. The long weapon, which is naturally 

 taken at first sight for a sting, is found only in the female 



Sirex; it is the ovi- 

 positor, or egg-laying im- 

 plement. On closer exam- 

 ination we shall notice 

 that it springs far forward, 

 from the under side of 

 the middle of the abdo- 

 men. If we are able to 

 handle a fresh insect, or 

 a dead one that has been 

 soaked for a few hours 

 in dilute potash solution, 

 we can make out that 

 there is an outer sheath 

 and a central core in the 

 ovipositor. Outside is a 

 pair of long, slender, two- 

 jointed valves, one on 

 either sidej within these 

 comes the actual boring 

 tool or core, a fine tube, 

 _. , „ • •. f c- /J- which can be separated 



Fig. 6i. — Borer or ovipositor of birex (diagram- . , . . . ^ 



matic) in side-view, transverse section and longi- WlthoUt injury intO an 



tudin.ll section. The valves are lightly shaded, ,,r,nf>r Vinlf thp <nnHA nnH 



the guide is darker, and the darts are black. Upper nail, tne gUiae, ana 



two lower components, the 

 darts. We have already seen that valves,* guide, and 

 darts are all present in the sting of a bee, and we find 

 answering parts in the saws of a saw-fly, and in the egg- 

 dart of an ichneumon. These various organs, so different 

 in form and mode of application, are all constructed on a 



* In the bee the valves are called sting-palps. 



