299 



THE STRUCTURE, BIONOMICS, AND ECONOMIC 



IMPORTANCE OF SAPERDA CARCHARIAS LINN., 



"THE LARGE POPLAR LONGHORN." 



By WALTER RITCHIE, B.Sc., B.Sc. (Agr.), 

 Carnegie Research Fellow, University of Edinburgh. 



(With Plates XX-XXIII and 25 Text-figs.) 



The assurance that a definite scheme of afforestation is to be established 

 in Britain has given a fresh stimulus to the study of insects injurious to 

 our forest trees. Already observations on the life histories and habits 

 of such forms have been called for, as without a knowledge of these, no 

 definite measures of control whether preventive or remedial can be 

 undertaken. 



The following intensive research on the structure, habits and life 

 history of Saperda carcharias Linn, the "Large Poplar Longhorn" is 

 therefore opportune, for to forester and nurseryman the species is of 

 primary importance as it may prove to be very destructive to healthy 

 young poplars. 



In the adult stage the Large Poplar Longhorn causes some injury 

 by feeding upon the leaves and by ovipositing in the basal portions of 

 the stems, but the greatest amount of damage is done by this insect, 

 while in the larval state, for by the larvae feeding and boring in the 

 stems, and occasionally tunnelling into side branches, healthy trees are 

 very soon killed or rendered worthless. 



The genus Saperda (Fabricus), to which our species belongs, contains 

 about fifty species, but of these only eight are European. In Britain 

 only three species are found, viz.: Saperda carcharias L., S. scalaris L., 

 and S. populnea L. Of these only the two first named have been found 

 in Scotland, and as far as we know, only S. carcharias and S. populnea 

 are of economic importance, the third species being known mostly to 

 Coleopterists and highly prized by them on account of its handsome 

 colouration. 



In England, S. carcharias is a fairly well known beetle, but in Scotland, 



