REPORT OF THE SOCIETY 9l 



applied after deposition as a cement to protect the soft shell during incubation. 

 In the accompanying illustration one of those menbranous coatings will be seen 

 detached on the left of the group of eggs. A specially designed cage 12" x 12" x 

 14" with glass sides was used in connection with this work. 



On hatching, the small larva 2 mm. in length, leaves the shell from the 

 underside of the egg and enters the bark at a point immediately below. The 

 minute cuttings and frass are passed back into the shell case from which emer- 

 gence has recently occurred and tunnelling begins at once. The young legless 

 grub slowly starts to eat its way down to the softer and more sappy areas, leav- 

 ing behind a very fine almost threadlike way of progress. This line of route 

 may be straight, winding or very tortuous; but usually it is fairly direct at the 

 start. Later on it becomes sinuous and very irregular, and where several lar- 

 vae are working together, as often happens, the tunnels cross and interlace 

 in such confusion that it is impossible to trace any particular one for any length 

 A closer study of the tunnels reveals certain slight enlargements here and there 

 along the line. These recesses mark the places where the larva has moulted 

 and as may be expected the distance apart of the first moults is small, but the 

 stadium increases gradually as the larva gets bigger. Five moults are required 

 to bring the larva to matirity. It is then a flat, legless grub, dull white and 

 about 22 to 25mm. long. The last resting point is important. The larva cons- 

 tructs in the woody area near the outer surface, a boat-shaped cell in which it 

 transforms. The beetle afterwards cuts its way to the exterior and emerges 

 through a lunar shaped or D-shaped hole on the bark, a characteristic which is 

 common to this genus, completing its lifecycle in one yard. 



Some observations were made in feeding and it was found that the beetles 

 partook sparingly of birch foliage. An effort was made to determine what 

 degree of preference was shown for various shade trees, and it was noticed that 

 a marked liking was exhibited for poplar, the leaves being freely eat en, specially 

 the young ones; while willow was next in choice and birch came last and was 

 scarcely touched. Elm the}' would not eat, nor any of the conifers. These 

 beetles are edge feeders, that is, they nibble small pieces from the leaf margins, 

 cutting out semi-circular patches here and there, as they go, seldom, if ever 

 severely attacking any one leaf. 



No effective control has as yet been devised for this pest despite conside- 

 rable work having been done toward this end. Severe pruning will tend to 

 check the spread of the beetles; but this is only a temporary measure and in the 

 end leads to the inevitable destruction of the tree. Where birches are planted 

 in large numbers along driveways, in parks and groves, it is well to take drastic 

 action by cutting out the infested tree and burning trunk and branches earl}' in 



