ELM BARK-BEETLE. 277 



rostrum. Antennal funiculus 7-jointed. First tarsal joint 

 much shorter than the succeeding joints together, the third 

 bilohed. Elytra scarcely declivous behind. Under surface 

 of abdomen flexed upwards from the base of the second 

 segment. 



They breed exclusively between the wood and bark of broad- 

 leaved trees, and sometimes make very regular galleries, which 

 generally cut deeply into the sapwood. Pupal chambers in 

 the outer layers of the sapwood. 



1. Scolytus Geoffroyi, Goeze (Elm Bark-beetle}. 



a. Description. 



This beetle is 4 to 5 mm. long, black, with the elytra brown ; 

 antennae and legs reddish brown. Front of head and rostrum 

 without any carina. Thorax broader than long, punctured, 

 the punctures becoming weaker towards the middle of its 

 upper surface. Suture of the elytra depressed from the base 

 to its middle ; their interstices broad, with two or three rows 

 of punctures. Third and fourth abdominal segments in both 

 sexes with a small tubercle. 



b. Life-Jmtory. 



Flight at the end of May and June, and sometimes again in 

 August. 



The eggs are laid in the bark of elms, 

 by preference in sickly trees. 



The larvae appear in July and the 

 beetles fly in August, and at once pro- 

 ceed to pair. The larvae of the second 

 brood hibernate in their borings, and 

 pupate in the following spring, gene- 

 rally in the bark or less frequently in 

 the sapwood. 



The beetles of this brood come out 



Fig. 136. Scolytus 



at the end of May. The holes of exit Geoffroyi, Goeze. 



are about the size of No. 5 shot. 



The generation is usually double on the Continent, and 

 apparently so in England in warm seasons. But in Britain, 



