105 



from these bark borers, which apparently have been the primary 

 cause of the trouble. The reason for this outbreak is not known, 

 although it possibly may have some connection with the great drought 

 of the preceding years, which may have weakened the pines and ren- 

 dered them easier victims of their insect enemies. 



EGG-LAYING RECORD OF THE PLUM CURCULIO. 



( CnnolrnchcJnn nenuphar Herbst. ) 

 By A. L. QrAiNTAXiE and Ralph I. Smith, College Park, Md. 



The accompanying table requires but little in the way of explana- 

 tion, aside from a statement of conditions under which the work was 

 done. 



On the morning of May 13, 1902, a considerable number of curculio 

 were caught from Japan plum trees in the college orchard, by the 

 usual jarring method. At this time egg laying had but just begun, as 

 very few punctures were to be found in the young plums. Ten 

 females were taken in copulation and each placed in a four-ounce 

 bottle. Three or four fresh plums were supplied daily to each insect, 

 and the number of eggs deposited was determined by dissection of 

 punctures in the plums as removed. It was found necessary to exam- 

 ine each puncture carefully, as a considerable number of punctures 

 and crescents were to be found in which no eggs were deposited. 

 The bottles were kept rather looselj^ corked and bits of filter paper 

 were placed in bottom of bottle to absorb any surplus moisture from 

 the plimis. 



A review of the table shows that the greatest number of eggs 

 deposited by anj- one beetle was 436, in the case of No. 5, with 276 as 

 the minimum for No. 1, of practically the same age. It is also to be 

 noted that the egg-laying period lasted for eighty days. The death 

 of beetles Nos. 1, 5, and 9. about August 1, would indicate that females 

 may live approximate!}- twelve months and that the broods would 

 overlap somewhat. 



Table showing egg-laying record of the plum curculio {Conolrachehis nenuphar), 1902. 



