POTATO FLEA-BEETLE. 



41 



10, a) ; the antenna is short, less than half as long as the man- 

 dible, subcylindrical, about twice as long as wide ; the palpus is 

 stout at base, apical joint conical, nearly as long as the antenna; 

 eyes apparently wanting; setae of head distinct, but few in 

 number. Thorax white, first segment with yellowish brown 

 chitinized dorsal shield, setose. The legs are short, stout, setae 

 few, tarsal claw simple, empodium distinct. Abdom.en white, 

 9 segmente'1. each segment provided with about 24 setae, the 

 spiracle distinct ; ninth segment with rounded apex, unarmed 

 except for the setae. Length about 5 mm. 



Fig. 10. 



ng. 12. 



The pupa (fig. 12) is white, becoming darker when it is ready 

 to transform. A transverse line of several setae is found on 

 each abdominal segment, those on the lateral line longest. Apex 

 of abdomen bifurcate; the forks slender, incurved and sharp. 

 Length 2.2 mm. 



During August 1912 larvae and pupae were to be found in 

 the ground among the young tubers but by the end of the first 

 week in September they had all disappeared. About the middle 

 of July the beetles of this generation begin to emerge in Maine, 

 becoming very abundant upon the potato vines and reaching a 

 maximum about the first of September. The first killing frost 

 in September marks the disappearance of the beetles to their 

 places of hibernation. Our own observations are confirmed 

 b}' those of Sirrine who says that the beetles emerge about 

 Jul>' 10 in New York, and by those of Jones who gives July 

 20 as the date in Vermont. 



