The Bronze Birch Borer. 



149 





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31 and 35). A day or two before transforming the pupse turn to the 

 dark bronzy color of the beetle. 



In making its hibernating and transforming chamber in the wood 

 in early autumn, the borer also extends its burrow up to the bark, so that 

 in the spring the newly transformed beetles only have to squeeze their 

 way out of the cell and eat their way through the bark. Larsen records 

 that the emergence of the beetles is rather a laborious process, as some 

 were found " with the forward parts of their bodies protruding for hours 

 making long rests between efforts to free themselves." Several of the 



peculiar shaped c.vit holes 

 of the beetles are shown 

 in Fig. 37. Eleven exit 

 holes have been covmted in 

 an area only two and a half 

 inches in diameter. 



The date of emergence 

 of the beetles in the spring 

 is of much importance in 

 connection with methods for 

 controlling it, and it varies 

 somewhat with climatic and 

 other conditions. Some- 

 times a few of them emerge 



V\G.2,-].—Exit holes of the bronze birch borer beetles as early as May 1st, but my 

 i)i the bark. Natural size. . ^ . '' . . .. 



observations and breeduig 



notes in New York indicate that most of them do not appear until from 

 May 15th to June ist, or even later. In 1900 Adams reported that none 

 of the beetles had emerged by June 3rd. The beetles feed on tender 

 foliage, evidently preferring other trees like the willow and poplars, as 

 Larsen has shown. 



Egg-laying. — I have not seen the eggs of this bronze birch borer as I 

 could not induce the beetles to lay eggs in my cages, but Larsen was more 

 fortunate and obtained evidence that they were laid in crevices of the bark. 

 He states that beetles " confined in a glass jar were found to be depositing 

 eggs on June 8th, and for a week or more afterward. Pieces of fresh 

 limbs were supplied, but the insects did not deposit their eggs upon these, 

 but moved about feeling for crevices with their long prehensile ovipositor 

 and having found a place, such as between the glass and the lower part of 

 the cork or under a piece of wood, from five to ten or more eggs were put 

 in one place. Copulation had gone on for some time before this. Great 

 activity was exhibited during the copulation and egg-laying. No observa- 

 tions were made on the development of the eggs." It is unfortunate that 

 the eggs were not described. 



