COLEOPTERA. 6 1 



The larvae emerge in July and August, and live and hibernate in 

 the wood, pupating in May of the 3rd year. 



The pupae lie head downwards in a chamber blocked with a plug of 

 wood-dust. 



The imagos emerge in June of the 3rd year. 



Generation biennial. The insect is rather common in a few parts 

 of Great Britain, chiefly in the eastern counties. 



Relations to the forest. The larvae bore into young, healthy 

 poplars, and also into willows ; aspen and black poplar up to 20 

 years old are specially attacked. Seedling trees are liable as a 

 rule to be attacked from their 5th year, and suckers from the 

 3rd year. 



The larvae make vertical galleries, which reach the centre of the 

 tree : these become gradually filled with wood-dust, which is forced 

 out of the tree by the grubs through a bore-hole, and becomes heaped 

 up at the base of the plants. The stem is attacked near the ground, 

 and reacts by developing a large irregular swelling, the bark of which 

 is fissured. Such perforated saplings are easily broken by the wind. 

 This insect is chiefly of importance where poplars are grown on a large 

 scale, as in France. It is sometimes associated with Sesia apiformis, 

 Fabr., and Cossus lignijierda, Fabr. 



The beetles in June and July eat roundish holes in poplar leaves,, 

 but this injury is unimportant. 



Saperda populnea, L. (Small Poplar Longicorn). 



Description. Beetle 8-13 mm. long, greenish-grey to dark brown, 

 covered with yellow-grey pubescence ; thorax with three lines of 

 pubescence ; elytra with the median line, and a broad lateral stripe, 

 and three or four spots on each side pubescent. Antennae blackish, 

 and each segment up to two-thirds of the length of the antennae with 

 grey pubescence. Larva 13-15 mm. long, yellowish, and resembling 

 that of the preceding species. 



Life-history. The female deposits her eggs in May and June in 

 cracks on the bark of young aspens, less commonly on other species 

 of poplar, sometimes on willows. Seedlings of 2 to 6 years old and 

 suckers are preferred. 



Generation biennial. The larva hatches in July, bores through the 

 bark, and eats a circular gallery round the sapwood. The stem, usu- 



