WOOD-WASPS. 355 



Family II. — Uroceridae (Wood-wasps). 

 Description of Family. 



Wood-Husps have straight filiform or setaceous antennae, 

 always shorter than the body, and with 11 to 30 joints ; 3 large 

 ocelli ; body long and cylindrical ; wings elongate with com- 

 plete venation. Legs with double trochanter, anterior tibiae 

 with a single apical spine. Abdomen sessile, with 9 segments ; 

 ovipositor elongate, projecting beyond the end of the abdomen, 

 and consisting of two lateral sheaths and a strongly serrate 

 median borer. 



Generation lasting at least two years. Larvae cylindrical, 

 soft, and whitish, with 6 legs, and a spine at the rounded 

 posterior extremity. Pupae soft and white. 



The larvae live chiefly in coniferous wood, in which the 

 perfect insects lay eggs with their long ovipositors. Pupation 

 also takes place in the wood, and the wood- wasp emerges by 

 a circular hole. 



1. Sirex javencus, L. {Steel-blue Wood-wasj)). 

 a. Description. 

 The insect attains a length of 12 — 30 mm. ( S ) and, including 

 ovipositor, 16 — 30 mm. ( ? ) ; thorax and abdomen steel-blue, 

 the latter in the J with the 4th to the 7th segment inclusive, 

 yellowish red ; in $ the steel-blue ground-colour of the 

 abdomen is iridescent, with a coppery sheen. Wings 

 yellowish, with brown margins. Legs chiefly reddish-yellow. 

 Ovipositor shorter than the abdomen. I.arva up to 30 mm. 

 long, with G very small feet, white. 



b. Life-ldstorij, el^c. 



The $ in July bores the bark of the Scots pine, usually of 

 trees in pole-woods, down to the sapwood, and lays an egg in 

 each hole. The larva eats out in the wood a curved burrow 

 of circular section ; at th'st it lives in the softer layers of the 

 sapwood, but after the first hibernation it bores deeper into 

 the tree, living on the resinous and starchy matters in the 

 burrow, the dust of which it packs behind it. 



After a second hibernation, in the early summer of the 3rd 

 year, it constructs a pupal chamber at the end of the burrow, 



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