256 MAINE AGRICULTURAL EXPERIMENT STATION. 1917. 



too late to be representative. Larvae entered soil in the labora- 

 tory on July 25 (1914), and if they had been allowed to develop 

 should have formed pupae on July 31. Eggs deposited on June 

 10 should produce pupae on July 21 since 41 days is the average 

 length of time required between the deposition of the eggs and 

 the pupal transformation. This estimate is probably not far 

 from correct, as eggs deposited on July 4 (1915) yielded pupae 

 on August 13 (40 days). The majority of these insects pass 

 through the pupal stage in August ; the extreme records which 

 the writer has for just-formed pupae are August 5 (1914) and 

 September 6 (1914). As was pointed out, July 21 would doubt- 

 less be nearer the range of possibilities than August 5. 



Nearly all of the hibernating adults are dead by late July. 

 The latest date to which one iTved in the laboratory is August 

 17 (1914). Adults become common again about the middle of 

 August, and this undoubtedly represents the appearance of a 

 new generation of the beetles. No adult which was bred in the 

 laboratory emerged earlier than August 20 (1914), but pupae 

 formed on July 21 should give adults on August 1. The extremes 

 of emergence are probably represented by August 1 and Septem- 

 ber 7. 



There is only one generation each year. There is no tend- 

 ency to pair among the individuals of the new generation, and 

 there is no indication that any of the pupae live over in the soil 

 until the following summer. Since they pupate very near the 

 surface in only the rudest sort of a cell, and since the pupal life 

 normally lasts but a few days, one would not expect any of 

 them to winter over. In the laboratory it was clear that all of 

 the pupae which did not transform were unhealthy. 



The writer was not able to make personal observations as 

 to the time when the beetles seek winter quarters in the fall, 

 and come out from their hibernating places in the spring. From 

 the data to which he has access, it seems probable that in Maine 

 the adults enter their winter hiding places early in October, 

 and desert them in the spring as soon as the leaves of the alder 

 are well expanded. Both in the fall and in the spring, the beetles 

 feed freely on the foliage. 



