Horntail:- As stiff and straight as a needle

Horntail:- As stiff and straight as a needle

A typical adult horntail is brown, blue, or black with yellow parts, and may often reach up to 4 cm long. The suborder Symphyta (Wood Wasps and Sawflies) includes those Hymenoptera which are structurally most primitive. There are approximately 500 species present in Britain. The 'tail' of the female is often mistaken for a sting, but the insect cannot sting and it is quite harmless.

The smaller horntail (Sirex noctilio) is only about half the size of the greater horntail, with pale brown legs and the rest metallic blue-black. It pierces the bark of pines to lay eggs. The smaller horntail ovipositor is very similar to the greater horntail, which is described as:

As stiff and straight as a needle, polished black, with slight notches in the pointed half. It is hinged, to permit of its being turned at right angles to the body. . . the female selects a tree that is not too healthy, and settles on the bole; then, turning down her boring instrument on its hinge, she drives it through the thick bark to the solid wood.

The insect then wandered off, walking rather jerkily over the log, the ovipositor held in its sheath beneath the body, its tip dragging along the bark behind her. 

As she went her antennae were in constant action, tapping the bark in front of her. About six inches from the spot where we first found her, having apparently discovered another position to her liking, the body was raised as high as possible on her legs, the ovipositor slipped from its sheath and the point inserted in the bark beneath the middle of her body, i.e. some distance, about an inch, away from the spot last explored by her antennae. The ovipositor was then perpendicular to the bark and to the general axis of her body, though this was now somewhat arched, while its sheath remained in its original position. ….Source