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JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



Of fourteen beetles marked June 24 from five to ten of them were 

 seen each day until July 1 when eleven were marked. From July 1 

 to 9 four to fourteen of the twenty-five were seen each day. Of fifty 

 beetles marked July 9 six to twenty-eight were seen each day until 

 July 23. About July 12 great numbers of smaller, more active, fight 

 green beetles appeared, which could be readily distinguished from the 

 prevailing form. Of fifty light green beetles marked July 15 one to 

 four were seen each day until July 23. Of fifty light green beetles 

 marked July 22 the record was: 23d four, 24th one, 25th none, 26th one, 

 27th none. 



One male beetle was found every day on a canna for twenty days. 

 Two females were found on a beet plant every day for eleven days. A 

 beetle will leave and return to a favorite plant from day to day where 

 it will frequently spend the night. All the beetles became active 

 about July 20. It was found by marking a large number that they 

 came from the Berkeley Hills down into Berkeley and Oakland. 



It seems that there is a period of comparative rest, followed by a 

 period of great activity. Each of these periods must have a definite 

 relation to some stage in the life history of the insect. 



Enemies. The tachina fly {Celatoria diahroticce Shim., Celatoria 

 crawii Coquillett), mentioned by Mr. Coquillett as one of the natural 

 enemies of Diahrotica soror Lee, was not very common in this section 

 of the country this year, for less than twenty examples of it were noted 

 among several thousand beetles. 



A spider, unidentified at this time, killed a few of the beetles. 



The only birds observed actually eating these insects were the purple 

 finch, the bush-tit, the linnet and the canon wren. 



Color Phases. On the 20th of June these beetles were not very 

 plentiful. Their wing covers were the normal leaf-green and the bodies 

 of the sexes were very much alike. By July 12 two color phases could 

 be detected in the field^ — ^the normal light green and a yellowish green. 

 By August 1 a third color phase could be detected — a pale faded green. 

 The latter was an old-age type for they soon died. But whether or 

 no it had passed through the other phases of normal green and yellowish 

 green, or represented a frail generation, is an unsettled question. 



Eggs. During the mating season females are very heavy with eggs 

 and the abdomens of the males are somewhat enlarged. It appears 

 that the eggs are rather completely developed before mating takes 

 place. At this stage the beetles are ravenous eaters and will stay with 

 one plant almost continuously, seldom leaving it. When attacked 

 these heavy forms simply let all holds go and roll down among the 

 leaves. If they fall to the ground they immediately begin to ascend 

 the plant as if anxious to get back to the feeding place. Before the 



