COLEOPTERA— SCOLYTID^. 101 



The brood-gallery is very simple, of a slanting direction, and the 

 larval galleries short and inconspicuous. 



The beetle is elongated, cylindrical, black, shining, and smooth. 

 Elytra with coarse crenate striae. Length 4 to 5 mm. 



Genus Hylesinus. 



This genus is a very important one to the student of forest insects, 

 inasmuch as all the species are strictly arboreal insects, and the grouj) 

 therefore has been termed " Hylesinidae or wood-devourers." Three 

 of the species feed on ash and one on elm. 



Synopsis of the Species. 



(1) Black or dark - brown, without scales. Size large. Mother- 



galleries single- or double-armed ; short, and horizontal. Larval 

 galleries very long and tortuous. Found in stiong bark of old 

 ash stems . . . . . . H. creyiatus. 



(2) Variegated with greyish scales. Size smaller. Double-armed, 



fairly long mother-gallery, and right-angled or slightly radiating 

 larval galleries. Lives in comparatively young ash stems or ash 

 poles .......//. fraxini. 



(3) Elytra black, witla yellowish dorsal streak. Short horizontal 



mother-gallery ; sometimes very long running larval galleries, 



at other times short crowded larval galleries. Lives in small 



branches of ash . . . . . H. oleiperda. 



(4) Beautiful variegated colour. Size very small. Double-armed 



short mother-gallery ; short larval galleries. Lives in elm. 



H. vitfatus. 



Hylesinus crexatus (Fabr.) 



This beetle is always recorded to have been found in ash in this 

 country, though two or three German writers give instances of its 

 being found in oak. It is also said to be widely distributed, but, so 

 far as I ascertained, it was not at all common in Cheshire, though 

 very common in Northumberland ; and it appears to be common in 

 Lincolnshire. 



It is by no means clear that the eggs are always deposited in felled 

 timber, though it may be looked for on recently felled old trees with 



