Characters of the Species. 



23 



but by the deeper, more livid color of the dark parts, and the 

 paler yellow of the light parts— the colors thus more strongly 

 contrasting. 



Just as the typical femur-rubrum is at once distinguished from 

 the typical spretus by the characters indicated ; so Atlanis, though 

 structurally nearer to spretus, is distinguished from it at a glance 

 by its much smaller size and darker, more marbled coloring. The 

 contrast is all the greater in the living specimens, and I have seen 

 no specimens of spretus that at aTl approach it in these respects. 



Whether this is the femur-rubrum as defined by DeGeer or by 

 Harris, it is almost impossible to decide, though Harris's figure of 

 femur-rubrum better represents it than the true femur-rubrum, as 

 subsequently defined by Thomas, and as found in Illinois and 

 Missouri. 



It has always been a question among orthopterists, 

 -whether spretus should be considered specifically distinct 

 from femur-rubrum, and Mr. Uhler has himself expressed 

 to me his doubts as to the two being distinct. This inde- 

 cision, which I myself very freely shared, may be attrib- 

 uted principally to the fact that the species just described 

 (Atlanis) has very generally been mistaken for femur' 

 rubrum, and that the accounts of this latter rising into 

 the air in swarms have in reality had reference to the 

 former species. The only reference to this longer-winged 

 species, in the East, that I am acquainted with, is that by 

 Dr. A. S. Packard, Jr., whose mention of the occurrence 

 of spretus in Maine and Massachusetts, as exhibited by 

 specimens in the museum of the Peabody Academy of 

 Science, (Am. Naturalist, Vol. VIII, p. 502), refers to this 

 species, as I have ascertained by specimens submitted to 

 me. This Atlanis as it occurs in the Mississippi Valley, 

 varies somewhat from the typical form as found in the 

 mountain regions of the Atlantic, being somewhat larger. 

 It is found with femur-rubrum in varying proportions, 

 sometimes predominating, at others in small numbers, or 



