1869.] REVIEWS, ETC. 335 



correspondence, which have been corroborated by succeeding 

 entomologists. In a letter to Hentz, dated Nov. 28th, 1825, he 

 says: — "The unarmed Oathophagus, (^Copris,) I have always 

 taken to be the female of Latebrosus. Individuals of the male 

 sex vary considerably in the size and projection of the thoracic 

 protuberance." This has been well established since by entomolo- 

 gists. Processes such as antennae, mandibles, thoracic projections, 

 clypeal developments are more prominent in the males of nearly 

 all insects. We have also taken this particular insect m coitii. 

 Again, in a letter dated Feb'y 26th, 1828, we quote what most 

 coleopterists will agree with. " Say's genus Harpalus is a kind 

 of magazine for doubtful species, several of which have the apex 

 of the elytra sinuato-emarg incite, as you observe in that common 

 and very beautiful species, H. Viridis, Say, or as Prof Peck 

 more judiciously named it (from its great variation of hues) — 

 Proteus. I am not sure but this species may prove to be the 

 viridi-ceneus of Beauvois, whose figure and description correspond 

 very well with our insect." This species we have been puzzled 

 with not a little on account of its variety of colours. Some in 

 our cabinet are of a bright metallic green hue, while others have 

 a cupreous appearance. The difference in colour we believe to be 

 mainly a sexual distinction. In reference to Say's genus, Feronia, 

 he says, "It is nevertheless a heterogeneous mixture, a complete 

 p 4 pourri, out of which several natural genera may be rescued." 

 We have found some of the genera of the Carahidce to have been 

 our Pons asinorum in Coleoptera. Species of this group closaly 

 resemble each other, and are very difficult to determine. Modern 

 entomologists, however, have done much to clear up this difficulty ; 

 among the foremost is Le Conte. 



The correspondence of this indefatigable worker (Harris) is in- 

 valuable to the entomologist, as many an idea discovered by himself 

 is here made known for the first time. In a letter bearing date July 

 28th, 1829, he says, " An excellent natural character by which 

 you may distinguish Colymhetes from Dytiscus (if you have not 

 the males) is that there is a projection of the anterior part of the 

 orbit over the eye in Cdymhetes, and not in Dytiscus. This 

 character had not beau noticed by other entomologists. You will 

 see it very distinctly in C. sadptilis." We have an acknowledge- 

 ment of this discovery in a letter of Hentz, Aug. 13th, 1829, 

 thus : " I thank you for mentioning your discovery for dis- 

 tinguishing between Colymhetes and Dytiscus. It is of the highest 



