XXX MEMOIR. 



His later entomological correspondence bore chiefly on the 

 topics covered by this treatise, as he had not the leisure to 

 enter on new ground. There exists, however, a letter to 

 Mr. Edward Newman, which should here be included, both 

 from its personal interest, and from its expression of opinions 

 on general scientific problems. The letter is in acknowledg- 

 ment of a work entitled " The System of Nature ; an Essay," 

 published in 1843 by that eminent naturalist, and by him 

 dedicated to Dr. Harris. 



" CAMBRIDGE, Jan. 7, 1844. 



" EDWARD NEWMAN, ESQ., 



" No. 9, Devonshire Street, Bishop's Gate, London. 

 " Dear Sir: 



"On the 23d of December I received the beautiful volume which you have 

 done me the honor to dedicate and send to me, and offer you my sincere 

 and respectful thanks for the same. The copies for the Public Library of 

 Harvard University and for the Boston Society of Natural History, were 

 duly forwarded as soon as received. 



" I have often read the very interesting letter which you wrote to me some 

 years ago; as well as your valuable contributions to the Entomological Mag- 

 azine. These, with your " Sphinx Vespiformis," your Grammar of Ento- 

 mology, and your very ingenious essay on the System of Nature, are full of 

 instruction. 



" In a private course of lectures on Entomology given to some of the stu- 

 dents of the University, four years ago, I endeavored to explain your sys- 

 tem, and made diagrams for the purpose, some of which still remain hanging 

 in the room where our excellent friend, Mr. Doubleday, saw my collection 

 of insects. I have often wished you would combine in one work all that 

 you have published on the classification of insects, and the characteristics 

 of the groups. Your papers on this subject in the Entomological Magazine, 

 with an abridgement of what is contained in the " Sphinx Vespiformis," 



