Walter Ritchie 343 



(15) Judeich und Nitsche. Lehrbuch der Mitteleuropaischen Forstinselrtenkunde, 



pp. 572-74, Bd 1, 1895. 



(16) Nusslin. Leitfaden der Forstinsektenkunde, pp. 81, 1905. 



(17) El Coleoptero Saperda carcharias L., parasitado. Bol. Soc. Entom. Espana 



Saragossa 1, No. 7, Oct. 1918, p. 150. 



(18) Chrystal, R. N. The Poplar Borer, Saperda calcarata Say. Agric. Gazette of 



Canada, vr, p. 333, April, 1919. 



DESCRIPTION OF PLATES. 



PLATE XX. 



On the left: Saperda carcharias Linn., male (ash-grey variety) at rest on a twig of 

 Populus tremula Linn. 



On the right: Saperda carcharias Linn., female at rest on a leaf of Pojmlvs tremula 

 Linn. 



The figures illustrate how the colouration of the beetles is to some extent effective as 

 a means of concealing them. 



PLATE XXI. 



10-12 year old infested stems showing flight holes of adults above, and tunnels o 

 larvae below. The flight holes are round in shape. 



PLATE XXII. 



Transverse sections of poplar stems badly tunnelled by larvae of S. carcharias. The 

 diameters of the sections are as follows: lower row, left to right, 1", 3" average, 4" approx. 

 Upper row, left to right, If", and \\" approx. Tunnels in centre of sections average in 

 diameter £". 



PLATE XXIII. 



Stem of 35 year old poplar, showing Assuring of bark consequent on earlier attack by 

 larvae of S. carcharias. 



