470 



BULLETIN 388 



FlG. 122. THE MATURE LARVA 



notum. The tip of the abdomen is armed with a pair of strong, incurving, 

 brown, chitinized hooks. 



Observations of European workers 

 The life history of the insect as outlined in the preceding paragraphs 



differs very markedly from that given by European workers, all of whom 



record the beetles as hiber- 

 nating and state that mating 

 and oviposition takes place 

 during the spring months. 



The latest worker, Scheidter 

 (1913), states that the beetles 

 emerge from hibernation about 

 the first of May, and that in a 

 short time mating takes place 

 and egg laying continues 

 throughout the summer. 



According to his observations, these eggs do not hatch until the following 



spring, so that each year both eggs and beetles of different generations 



hibernate. He concludes that with this insect 



there is a complete generation every two years: 



beetles emerging in 1910 hibernated, and laid eggs 



in 1911; these eggs hibernated, and hatched in 



the spring of 1912, the beetles reaching maturity 



in late July and August; these beetles in their 



turn mated and oviposited in the following spring. 

 Munro (1914) finds that in northern Scotland 



there is a complete generation every year, the 



beetles hibernating and ovipositing during the 



spring months. 



Caesar (1916) finds that in Ontario consider- 

 able numbers of the beetles appear in the early 



spring months, but he does not know whether 



these have hibernated as beetles or as larvae or 



pupa?. He also failed to determine whether they 



lay eggs during the spring months. 



FlG. 123. THE PUPA 



It would thus seem that the life history and habits of this insect are com- 

 plex and vary greatly. 



CONTROL MEASURES 



When the writer began work on the poplar and willow borer, no efficient 

 control measures had been devised. The general recommendations had 

 been the cutting-out and destruction of infested trees. Schoene (1907 a) 



