ZOOLOGICAL NOMENCLATURE. 7 



abbreviated if the context is such that the abbreviations will be read- 

 ily understood. Thus the name of the Black Merlin may be written 

 Falco c. suckleyi or F. c. suckleyi. 



Subspecific names are used by entomologists not only to distinguish 

 geographical races, but also to distinguish the different forms of 

 dimorphic and polymorphic species. A good illustration is afforded 

 by a certain species of Swallow-tail Butterfly common in the Atlantic 

 States. This species exists under two distinct forms; one of these is 

 yellow marked with black, and has long been known as Jasoniades 

 turmis ; the other is almost entirely black, and has been known as 

 Jasoniades glaucus. At first it was supposed that these were different 

 species ; but in recent years the two forms have been bred from eggs 

 laid by the same female. It is thus evident that the two forms repre- 

 sent a single species. And as the form Caucus was first described its 

 name is given to the species, which is now known as Jasoniades 

 glaucus. This name Jasoniades glaticits is used when reference is 

 made to the species as a whole. But if one wishes to refer to the 

 black form alone, it is distinguished as Jasoniades glancus glaucus ; 

 while the yellow form is distinguished as Jasoniades glaucus turnus. 



In the illustrations just given the dimorphism occurs in the same 

 generation. But many instances are known where the dimorphism is 

 seasonal. Thus in the case of certain insects which pass through two 

 or more generations in the course of a year, the different generations, 

 or some of them, differ markedly in form or coloring from the others. 

 These differences in many cases are so great that the different genera- 

 tions of the same species were believed to be distinct species till they 

 were bred from each other. It is therefore often desirable to distin- 

 guish these different forms by subspecific names. Thus Iphiclidcs 

 ajax is a species of Swallow-tail Butterfly which exists under three 

 distinct seasonal forms: an early spring iorm, I. ajax marcellus ; a 

 late spring form,/, ajax telamonides ; and a summer form, /. ajax 



ajax. 



The name of a genus or of a subgenus is always a single word, 

 and should be a noun in the singular number and nominative case. 



The names of all groups of genera (i.e., families, orders, classes, 

 and branches) consist each of a single word ; and this word should 

 be a plural noun in the nominative case. 



The following practices regarding the forms of zoological names 

 are now almost universally followed : 



The names of all groups in zoology, from kingdom to subgenus 

 inclusive, are written and printed with a capital initial letter. 



