1899] MOTTLED WILLOW WREVIL. 135 



W. R. Fisher, p. 199) of larval burrows of (!. laprdlii causing injury 

 to an Alder stem, about three-quarters of an inch across, they may 

 go in a more or less slanting direction from one side of the stem 

 to the other. In these galleries the frass, or "bore-chips," is very 

 noticeable, and so is the condition of the outside of the shoot after the 

 attack. 



In the piece of Willow stem before me, taking the half circumfer- 

 ence of the split stem, one inch in diameter, there are four large 

 orifices to tunnels in a length of four inches. The holes themselves 

 are about a quarter of an inch across, but the discoloration and injured 

 state of the surrounding bark makes them very conspicuous. Each 

 hole is in a small brown tunnel- shaped cavity apparently formed by 

 gnawing, and round each external orifice is a slightly raised border of 

 brown bark, forming (for much of the circumference) a thoroughly 

 defined ring of about an eighth of an inch in width ; at the other part 

 the border is of much greater size. It is irregularly enlarged to a 

 brown patch of nearly three-quarters of an inch in length from the 

 orifice, and of varied and irregular width, up to as much as half an 

 inch or more, and along the centre of this enlarged part tlie bark is 

 split into an irregular fissure. Tlie figure given by Dr. Bernard Altum 

 accompanying his notes on the attack of this C. iapathi gives a good 

 idea of the appearance of these rings of injured bark.* 



Within these tunnels the larvre turn to pupal state, and thence to 

 the developed beetles ; but how long the period may be that is required 

 for the transformation is a point on which different opinions are ex- 

 pressed by the two well-known German writers to whom we are 

 indebted for detailed observations of the life-history. 



Dr. Taschenberg i considers that cusfomaiilij the generation is of 

 one year, the larv£e being to be found in August, and completing deve- 

 lopment before winter, but still that this is not always the case. 



Dr. Bernard Altum (see reference below) states that the larval 

 attack is in two distinct parts. Firstly, that of the superficial attack 

 under the bark in the first summer ; and after hibernation, the second 

 stage of attack into the sound wood occurs in the second summer. 

 "Consequently these insects have a two years' yeneration'' (B. A.). 

 Very minute details will be found given in the papers referred to, but 

 I believe the above is sufficient for general purposes. 



Prevention and Remedy. — Examining whether signs of infestation 

 are present in the stems, and, if so, cutting down (so far as is possible) 

 all that show presence of it, and burning them, before the beetles are 



• See ' Forst-Zoologie,' von Dr. Bernard Altum, vol. iii., Irisekten, pt. i. 

 p. 208. 



t See * Praktische Insektenkunde,' pt. ii. p. IGl. 



