192 LEPIDOPTERA. 



Wood Wasps {Sivicijltn or Uroi-fridw). 



The second group are the ^Vood Wasps or Siricidn'. The 

 Sirex-flies have a long freely projecting ovipositor, by means of 

 which the female places her ova in the vcood of coniferous trees. 

 Two species are destructive to conifers in England, namely, the 

 Giant Sirex (Sirex 'ji'jas) and the Steel Blue (S. juvencus). 

 Both are large insects, the former species often being an inch 

 and a quarter long in the female, with four tawny wings and 

 black and yellow body ; S. juvencus is somewhat smaller, and 

 beautiful steel-blue in colour. The ova laid under the bark of 

 the trees hatch into white, nearly footless, larvae, which eat their 

 way into the very heart of the wood, forming long tunnels 

 which are partly blocked up as they progress with their "frass." 

 They seem to live in this position some nine months, and 

 pupate somewhere near the bark, so that in the summer when 

 the Sirex is mature it can easily eat its way to the open. The 

 adults have extremely hard and strong biting mouths, and leave 

 behind a large round hole in the trunk that we very often 

 notice on pine-trees. Numbers of larvie usually inhabit each 

 tree, so that it is soon killed. It is always advisable to cut 

 down and burn any tree showing symptoms of their attack in 

 the winter when the borers are at home. 



LEPIDOPTERA, 



OH Butterflies axi> IMoths. 



The liCpidoptera or scaly-winged insects are the Butterflies 

 and Moths. The former are known as Diurui or lihopalocera, 

 and have always club-shaped antennse (fig. 95, 1), and the wings 

 are always held vertically over the back when in repose. They 

 are day-fliers. The moths or Hilerocera have either thread- 

 shaped, feathery, or pectinate antenna; ; the \vings are usually 

 folded over the back in^reposc. 



