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XVII. Of the Insect called Oistros by the Ancients, and of the 

 true Species intended by them under this Appellation : in rcpli/ 

 to the Observations of JJ . S. MacLeay, Esq., and the French 

 Naturalists. To which is added, A Description of a new Species 

 q/CuTEREBRA. Bi/ Bruci/ Clarh, F.L.S., and Foreign Mem- 

 ber of the Royal Academy of Sciences of Paris. 



Read November 19, 1826, and February 20, 1827- 



In the 14th volume of the Transactions of the Linnean Society, 

 is a communication written by my friend W. S. MacLeay, Esq., 

 intended to prove that the tiy, intitled Oistros by the ancients, 

 was not the insect so named by Linnseus, but that it probably 

 belonged to the present Linnean genus Tabanus. 



Being of a contrary opinion, I am led once more to address 

 this learned Society, to lay before them the grounds on which it 

 is founded, that naturalists may not incautiously and too hastily 

 adopt the above conclusion, and that they may avoid the con- 

 fusion which change of names and counter changes always pro- 

 duce in science. I am also led to this undertaking in order to 

 vindicate Linnaeus himself, our great master, and such distin- 

 guished naturalists as Vallisneri and Reaumur, with whose 

 views on this subject I wholly concur. Nor is the justification 

 of myself wanting as a motive to induce me to re-examine the 

 subject, having formerly sent to this Society a dissertation of 

 some extent on the genus Œstrus, unfolding some curious dis- 

 coveries 



