June, '081 JOURNAL OF ECONOMIC ENTOMOLOGY 207 



an accumulation of 4016.8° F. (read) or 4002.5° F. (measured), 

 while those that were thus undisturbed required an average of 63.8 

 days under an average mean temperature- of 70° F., with an accu- 

 mulation of 4468.78° F. (read) or 4453.3° F. (measured). 



Injury 



The insect injures the plants both as an adult and as a larva, but 

 in New Hampshire the adult is much the more serious, for it attacks 

 the plants while they are young and when they are less able to with- 

 stand injury. Frequently it will attack the stalk just below the sur- 

 face of the ground and eat almost, if not quite, through it. Many an 

 injured plant will not be eaten enough to kill it, but the wound will 

 harden and the plant grow, even until it has begun to run, when the 

 first hard wind snaps it off at the point of injury. If the insects are 

 abundant and prompt measures are not taken, the whole crop will be 

 utterly destroyed in a few days. Even when plants have reached a 

 height of three or four inches and have grown strong and stocky, the 

 beetles will sometimes concentrate, especially on replants, and destroy 

 them. 



In New Hampshire the larvfe are rarely sufficiently abundant to do 

 serious damage, although plants may be found every year which have 

 been attacked and killed b}^ them. Larvte have been found among 

 squash roots in the field, but there was little evidence that they had 

 been feeding on the finer roots and only a few instances where they 

 were found feeding on the larger ones. In potted squash where the 

 larvae were relatively more abundant, they were found feeding within 

 the roots and the stems, even going as high as three or four inches 

 above the ground. Certainly where the larvae were sufficiently abun- 

 dant, they would do serious damage. 



From the time the plants begin to flower, the beetles desert the fol- 

 iage and feed on the pollen until driven into winter quarters in the 

 fall. 



Natural Enemies 



Certainly at least one, if not two, dipterous parasites prey on 

 adult beetles, and doubtless many such predaceous enemies as ground 



2The average mean temperature for the whole period was determined in 

 this case by dividing the accumulated temperature by the total number of days 

 required for the transformation, and the accumulated temperatures were de- 

 termined by adding the average accumulated temperature for egg-state to aver- 

 age accumulated temperature for period extending from hatching to adult. 

 Circumstances rendered the data such that the average mean and accumulated 

 temperatures from egg-deposition to adult could not be computed directly. 



