Coiitrilbiitions to tlie Descriptire and Systematic 

 Coleopterology of North America. 



PART I. 



By Tiios. L. Casey, Lieut, of Eng'rs, U. S. A. 



The following essay is given to the public, with the view of con- 

 tributing another mite to the written descriptions of our American 

 fauna, as well as of rendering it possible to identify for coiTespondents 

 many distinct species, at present scattered unnamed through our type 

 collections. Many of them belong to genera, to the apparent confu- 

 sion of which, it may be regretted by many that any addition has 

 been made, and in these cases I have made the descriptions as full 

 and exact as it lay in my power. If they ever serve to identify the 

 species, they may be considered to have done their duty. 



These remarks apply particularly to the genus Harpalus, in which 

 the green metallic species are separated by the number and arrange- 

 ment of the setigerous punctures on the epistoma. Whether these 

 species are valid or not, time and experience can alone demonstrate, 

 but it must be affirmed here as a conviction that much of the trouble, 

 confusion, and consequent neglect of the species in this genus, is the 

 result of a careless study and separation of them, and that there is 

 much less variation in the individuals of species, which have been 

 thoroughly investigated and minutely defined, than is commonly 

 supposed. 



This is certainly the cause of the trouble in the case of H. viri- 

 diceneus, which will be seen later to have been made up, in most 

 cabinets, of individuals belonging to five distinctly characterized 

 species. Knowing these species to be distinct, it is very easy after- 

 wards to see many differences, which were overlooked while they 

 remained mixed up in confusion ; and this, for a reason analogous to 

 that which renders it much easier for an astronomer to detect a faint 

 star or satellite of a planet, when once it has been discovered, and its 

 Published August, 1884. 1 



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