ON VARIATION IN THE MOTHS. 223 



tracks, some of which are marvelously like bird's tracks, we should 

 not come upon exactly that series of transitions by which in former 

 days the reptile was connected with the bird. 



I don't think, ladies and gentlemen, that I need insist upon the 

 value of evidence of this kiud. You will observe that, although it 

 does not prove that birds have originated from reptiles by the gradual 

 modification of the ordinary reptile into a dinosaurian form, and so 

 into a bird, yet it does show that such a process may possibly have 

 taken place, and it does show that, in former times, there existed 

 creatures which filled up one of the largest gaps in existing animate 

 nature, and that was exactly the kind of evidence which I stated to 

 you in starting we are bound to meet with in rocks if the hypothesis 

 of evolution be correct. 



In my third and last lecture I will take up what I venture to call 

 the demonstrative evidence of evolution. 







ON VARIATION IN THE MOTHS. 



By AUG. K. GROTE, A. M. 



THERE are a large number of different kinds of moths, inhabiting 

 North America and Europe, which entomologists have classified 

 under the technical family term, Noctuce. Of this family, 1,028 differ- 

 ent species have been catalogued as European. There being very many 

 students, and a sufficient time having elapsed to secure a thorough col- 

 lecting throughout the territory, this number may be taken as suffi- 

 ciently corresponding with the actual representation of the family in 

 Europe. In North America nearly 1,200 species are now catalogued, 1 

 but, since much of our territory remains to be explored in this re- 

 spect, we may expect considerable additions to the number of known 

 Noctuce inhabiting our continent. The greater number of the spe- 

 cies may be easily distinguished on comparison, the American from 

 the European. There are, however, certain American species which 

 differ but very slightly from certain European, and hence are generally 

 called " representative species," or " species of replacement." For 

 instance, Apatela occidentalis (G. and R.) " represents " the European 

 Apatela psi (Linn.) ; Agrotis Normanicma (Grote), the European 

 Agrotis triangulum ; Calocampa nupera (Lintner), the European 

 Calocampa vetusta ; Catocala relicta (Walk.), the European Cato- 

 cala fraxini, etc. 



Although the number of such species appears relatively small, 



" List of the Noctuidae of North America, 1875 '76." Buffalo, Reinecke & Zesch. 



