90 PROTECTION OF PLANTS — 1922-23 



packs the tunnel tightly behind it with borings as it goes forward. However, 

 the larvce show other signs quite distinctive, and one of these is a certain wavy 

 character of the bark. The outer surfaces of the branches and trunk may often 

 be raised in small undulations due to the operation's of the grubs as they tunnel 

 just below in the outer bark. Another good sign is the presence of dirt}'-, red- 

 dish-looking patches on the white bark surfaces, often with rusty-coloured sap 

 trickling from them. These spots are quite small at first but later may reach a 

 size of several square inches, presenting very unsightly markings which greatly 

 detract from the beauty of the tree. 



The adult belongs to that destructive group of wood-boring insects, the Bupres- 

 tids which are commonly known as metallic beetles. It is slim in outline, olive- 

 bronze in colour and about 10mm long. The sexes are quite similar in appear- 

 ance except that the male has a slight depression on the first abdominal segment. 

 The beetles are very active specially during the bright warmer parts of the day. 

 They fly rapidly from branch to branch and chase one another up and down 

 the bark with great alacrity. They have a habit of raising the wing covers as 

 if about to fly and of stretching and exposing themselves to the direct sunlight 

 where they will lie basking for long intervals at a time. If approached, even 

 ver}^ cautioush^, they at once display signs of uneasiness; and if in the slightest 

 waj'^ disturbed will fly awa}^ quickly , disappearing as by magic. At other times 

 they will dodge the observer from side to side of the trunk in order to elude him. 

 If approached near enough to be touched, they almost invariably feign death 

 and drop to the earth; although occasionally they hold tenaciously to the bark 

 surfaces and will not give up except forced to do so. 



Under close conditions in the laboratory, mating was commonly observed. 

 This occurred early in June and egg laying began immediately afterwards. 

 Fresh birch sticks were cut and placed in the cages for the beetles to oviposit on. 

 The females would examine the surface of these with great interest, feeling the 

 bark with their short serrate antennr, running rapidly from one depression to 

 another, probeing these with their long ovipositors as they sought suitable loca- 

 tions to deposit their eggs. 



Oviposition was carried on during the warmer parts of the day, the bright 

 sunshine being a marked simulant for activities. 



It was the writer's good fortune to discover the eggs of Agrilus anxius dur- 

 ing summer of 1920, after several seasons study on this problem. The original 

 description is now given here for the first time. The egg is oval in outline, 

 much flattened on two sides, length] .25 to 1 .50 mm.; width. 75 to 1 mm.; chorion 

 soft, wrinkled and finely reticulated; pale cream-white when first laid changing 

 to yellowish tints, chiefly at the pole ends. Adheres well to the surface and is 

 coated over with a very thin, serai-transparent white filament. This last is 



