124 The Ottawa Naturalist. [Oct. 



characters, either in any one locaHty, or differing in one locaHty 

 from another. Such are called constant species. Others may 

 be very constant in any one locality, yet appear in more or less 

 modified forms in different localities, according to geographical, 

 geological, or climatic conditions. Others may be constant in 

 one locality, but show considerable range of variation in another; 

 or may vary to a greater or less degree towards a certain form in 

 one place, and towards quite a different form in another. But 

 few that vary at all in any locality, vary to the same degree, 

 or within the same limits wherever they occur. In short, whilst 

 some species do not vary to any extent anywhere, others seem, 

 as it were, to lend themselves enormously to local variation. 

 In some instances dift'erence of food-plant is accountable in a 

 great measure for variation in size and color, and it has been 

 observed that the fact of a larva confining itself to different food- 

 plants in different parts of the country does not necessarily 

 indicate different species. Breeding, and careful records of early 

 stages, have often resulted in a distinct specific relationship 

 having been traced through between forms presenting somewhat 

 striking differences in dift'erent habitats, which might otherwise 

 easily have passed as distinct species. The expression "specific 

 relationship" must not be taken to mean positive "specific 

 identity," as the legitimate use of that expression will depend on 

 the concise meaning attached to the word "species," briefly 

 discussed in a previous paper. 



Some species have seasonal varieties, that is, they pass 

 through their entire metamorphoses more than once a year, and 

 the different breeds assume different characters, according to the 

 season or length of time spent in larval and pupal stages. Others 

 show dimorphic variation, sometimes in one sex, sometimes in 

 both. That is to say, two different forms, suggesting two species, 

 can be bred from the same batch of eggs, even without any 

 actually intermediate form appearing at all. And this may 

 occur regularly in some localities, never in others. In both the 

 foregoing instances, as in many others, unfamiHarit}^ with the 

 species concerned has resulted in the separation of what are 

 merely varieties into species. In some years too, a species shows 

 a stronger tendency to a certain form of variation than in others. 



A species varying differently, or appearing under a modified 

 form, in different localities, is said to exist in those localities in 

 the form of a "local race," which is sometimes referred to, with 

 doubtful justice, as an "incipient species." It is questionable 

 whether a truly distinct species can ever be evolved whilst 

 direct specific relationship can be maintained by interbreeding, 

 on what may be called, for convenience, the confines of their 

 range, or where the races meet. Complete isolation from blood 

 relationship for a lengthy period under special conditions, is 

 probably necessary before a race can be said to begin to exist 



