77 



HENTZ TO HARRIS. 



CHAPEL HILL, Aug. 13, 1829. 

 I am willing to confess to vou my want of acumen in finding 



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so little difference between your 582 (my 13), marked by you 

 Bracliinus fumans, and the European B. crepitans, that I can 

 only look upon them as varieties. Perhaps I am quite wrong, 

 but I fear it is too much the fashion with our brethren natural- 

 ists of Europe, and even Mr. Say, to make new species with 

 slight varieties. It is true that B. crepitans is smaller, but my 

 13 varies from | to more than 4- an inch. We ought to inves- 

 tio-ate thoroughly, but we must beware against the danger of 



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creating confusion by making too nice distinctions. Insects of 

 the same species vary considerably in color, in size and in 

 shape, even in the same country. I have taken in the act of 

 copulation insects which accidentally (not sexually) varied 

 enough in shape to create a distinct species, if they had been 

 taken separately. 



I thank you for mentioning your discovery for distinguishing 

 between Colymbetes and Dytiscus. It is of the highest value, 

 where we must, in the state of the science, have the two sexes 

 to ascertain genera. I wish you would try to find some char- 

 acter of that kind for the Tlwracici. I think I have a Scym- 

 nus. I .always thought it related to Coccinella, but have not 

 yet studied it, nor is it labelled. It is common on corn stalks, 

 where it runs like Coccinella ; there is a brown spot at the end 

 of the elytra. 



I have now Megacepliala virginica and Carolina. The lat- 

 ter was sent to me by a friend from Newbern, never being 

 found here. The other (M. virginica} is also a beautiful insect. 

 The mandibles of the $ , in all specimens I have seen (six or 

 eight), are shorter and more curved than in the $ , and on the 

 right side they have three teeth of great strength, the middle 

 one longest ; on the left side the middle tooth is shortest. This 



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