CURCTILIOS THAT ATTACK WALNUT AND HICKORY. 7 



nuts (PL I, C). and in excavating the egg chamber in such nuts the 

 female beetle takes her position on this withered part of the blossom, 

 and, with her head pointing toward the nut, proceeds to excavate the 

 crescent-shaped egg chamber. On account of her method of work 

 the concave side of the crescent faces the tip. (PI. II, A.) It is 

 not unusual to find a young butternut with a row of these crescent 

 marks completely encircling the blossom end. 



As the nuts develop and the husk becomes tougher the beetle 

 changes somewhat her method of procedure, and instead of cutting 

 out the crescents for her eggs, places them in simple cavities gouged 

 into the side of the nut through small openings in the skin. Such 

 cavities are usually arranged in groups, the skin about the wounds 

 being marked by dark stains from slight exudations of juice and from 

 excrement voided by the beetle during the excavating process. These 

 groups of punctures often contain half a dozen eggs each, one having 

 been found by the writer which contained 11. 



NATURAL ENEMIES. 



During this investigation two species of dipterous parasites have 

 been reared in TTest Virginia from larvse of the butternut curculio. 

 These have been determined by Dr. J. M. Aldrich, of the United 

 States Xational Museum, as Chaetochlorops inquilina Coq. and Cho- 

 lornyia longipes Fab. Both species are rather abundant, the first- 

 named, especially, rendering good service in holding the curculio in 

 check. Other investigators have reared the following species from 

 this host: Metadexia basalis G.-T., Cholomyia inaequipes Bigot, 

 M yiophasia aenea Wied., and Sigalphus curculionis Fitch. 



THE BLACK-WALNUT CURCULIO. 6 



In June, 1919, the ground beneath bearing black walnut trees 

 (Juglans nigra) at French Creek, W. Va., was found to be strewn 

 thickly with young nuts the size of small marbles. Examination 

 showed that each nut contained a single dirty-white larva half an 

 inch or less in length. A quantity of the nuts were collected and 

 placed in rearing jars with the expectation that in due time beetles 

 of Conotrachelus juglcmdis would be reared therefrom. When the 

 beetles appeared, however, they were slightly different from C. jug- 

 Icmdis, and specimens submitted to Mr. E. A. Schwarz, of the 

 T'nih-'i States Department of Agriculture, were determined as Cono- 

 trachehi8 retentus Say, ;i species the habits of which bad hitherto 

 been practically unknown. Further observations proved that this 

 species attacks commonly the young fruits of black walnut in many 

 localities in the eastern pari of this country. 



OonotracheUi retentus Bay; suborder Ethynchophora, family Curcullonldae, tribe 

 rbyncblnl. 



