16 



but, having only one species for it, as well as for your Steno- 

 thorax^ will it serve the science as much as your other divisions ? 

 The great defect of the system of the Father of Natural 

 History was that it had often too many species in the same 

 genus ; it became necessary to make more divisions, but some 

 authors fell into the opposite defect, creating a confusion with 

 an inteYition to simplify. Now the genus Melolontha, a division 

 of Linnaeus' enormous genus Scarabeus, is still too large, and I 

 conceive your divisions will be highly useful, when you can 

 comprehend in them a certain number of insects. Should you 

 find more species for your seventh subgenus I should think it 

 an excellent one ; and I doubt not your being able to do so, 

 and, moreover, your adding new divisions as you study the 

 minute parts of the insects of that genus and others ; for I do 

 not doubt that every species is possessed of some mark in its 

 formation, which, independent of its colors, could distinguish it 

 from the rest ; the object is to find such a mark, not common 

 to the whole genus, occurring in a sufficient number of species 

 to permit us to separate them into a limited division, which 

 may be easily run over by the student. 



Your proposed division of the genus Plater is very necessary ; 

 and I hope you will make it. Should you find a similar one 

 for the genus Buprestis you would much improve the science. 



I subjoin the dimensions of the elytra of the Chremastochei- 

 lus, measuring its length from its apex at the suture to its union 

 with the thorax near the scutel. As the thorax, or the head, 

 is more or less bent, the measurement might be more incorrect 

 if I took the whole insect, than if I gave you the length of 

 the elytra. 



O. piger. Largest, nearly -^^ in. ; smallest, a Httle more than 

 -5^ in. 



C. castanea. Largest, a little more than -^ in. ; smallest, 

 fully j^ in. This species varies less in size than 0. piger. 



