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Vol. XXX. LONDON, FEBRUARY, 1898. No. 2. 



ON THE HISTORY AND HABITS OF THE "WOOD EN- 

 GRAVER " AMBROSIA BEETLE— XYLEBORUS XYLO- 

 GRAPHUS (Say), XYLEBORUS SAXESENI (Ratz.) 

 — WITH BRIEF DESCRIPTIONS OF 

 DIFFERENT STAGES.* 



BY A. D. HOPKINS, ENTOMOLOGIST, \V. VA. AGR. EXPT. STATION. 



The Ambrosia beetles of the Scolytid genus Xyleborus present many 

 features of interest to the student of systematic and economic entomol- 

 ogy', and in Xyleborus xylographus we find a cosmopolitan species of 



unusual interest. 



History. 



It was described by Say in 1S26- from specimens "sent to him by 

 the younger Rev. J. F. Melsheimer from the Melsheimer collection, with 

 the manuscript names and notes by the elder Rev. F. V. Melsheimer."^ 

 Say's erroneous reference to the habits and galleries of the species, pub- 

 lished with the description, was (as suggested by Schwarz) due to his use 

 of Melsheimer's notes on a different species, probably a Pityophthorus, 

 Pityogenes or Tomicus species. This was the cause of much confusion 

 in subsequent literature on the -species. The Tomicus xylographus 

 referred to at length by Dr. Fitch'*, and subsequently quoted by Packard' 

 under Xyleborus xylographus, was evidently Tomicus ccelatus, although 

 the galleries illustrated by Fitch resemble the work of a Pityophthorus 

 more than they do that of T. ccelatus. 



Some years after the publication of Say's description, Ratzburg'' 

 described the same thing under the name Xyleborus saxese?ii, which, 



*Read by title before the W. V'a. Academy of Science, Arts and Letters, Dec. 

 7th, 1897. 



1. Ambrosia Beetles of the United States; H. G. Hubbard; Bull. No. 7, new 

 series, U. S. Department of Agriculture, Div, of Entomology, 1897, pp. 9-30 ; also 

 Year Book, 1896, pp. 421-430. 



2. Bostrichus xylographus. Jour. Acad. Nat. Sci., Phila. , 1826, Vol. V., p. 256. 



3. Catalogue of Insects of Pennsylvania, 1806. 



Quotation from Schwarz in Proc. U. S. Nat. Museum, Vol. XVIII., p. 610. 



4. Tomicus xylographus, Fitch, 4th Rep. Ins. of N. Y., 1858, p. 716. 



5. Bull. 7, U. S. Ent. Com., Insects Injurious to Forest and Shade Trees. 



