- 5 8- 



2nd. — One must in his observations take account only of distinctions 

 which are possessed by every species o! the same genus and every spe< i- 

 men of the same species as well as in both sexes if the female is perfectly 

 developed 



As based upon these laws venation, head and palpal structure, the 

 legs and their armature are none to be reckoned in generic determination. 

 Classification practically rests ist— upon the visible and evident shape of 

 the wings, and 2nd — upon the method of the design of the markings of 

 the wings. For the first account is taken of the various edges, whether 

 rounded, ungulate, straight or concave — of the various angles, whether 

 sharp or rounded ; for the second account is taken of thenumberol 

 lines upon the fore and hind wings, and their shaping in lines. Lands, 

 pi uiils, &c. 



Following this, the author gives Ins rules ol nomenclature. Ax.. 

 tables of the altitude and geographical distribution of species. I'hese are 

 followed by a synopsis of genera and a general description and systematic 

 arrangement of species. The three plates given so far with the work are 

 intended to place before the eye the author's ideas of influences, cold, 

 heat, elevation, plant life, etc., which in the North temperate Zone have 

 affected and which now to an extent modify its Geometrid Fauna. 



With regard to the System of the author, after a detailed examination 

 we fail to see how it can be called more natural or less artificial than 

 systems based upon venation or the structure of the various parts ol the 

 body. We fail to see either right or reason in forbidding for the deter- 

 mination of genera the use of structural distinctions which are ascertained 

 only by use of the microscope. We fail to see anything of exactness 

 gained by using for determination things so variable as wing shape, 

 or so wonderfully changeable as the design of the markings upon the 

 wings. We fail to see that this latter which is unsafe for specific deter- 

 mination, can be used in any way as a basis for generic distinction. The 

 system seems to be the outgrowth of a feeling we have often realized, viz. : 

 that the systems of the past are unsatisfactory, and to an extent artificial. 

 But we would not think it either rational or necessary to cast away all 

 the past has done, because we find its work incomplete or disappointing. 



Some of the innovations of the author we are inclined to endorse. 

 Anion- the number we note the Latinizing and correct spelling of generic 

 names, as Eubcea for Eubyja, Marmoropteryx for Marmopteryx, Loxo- 

 mma for Lozogramma, &c. 



The author in his Bibliography makes no reference to the Bulletin of 



the Brook], Ent. Soc, Entomologica Americana, Papilio, the Canadian 



Entomologist, or any works issued by our Government, except Dr. 



ird's Monograph. Dr. Packard's work seems to have been the sole 



