Occasional Papers of the Museum of Zoology 5 



In subsequent pages I have made some further attempts 

 at the discrimination of forms of less than specific vakie 

 Avhich may intergrade to some degree but still obtrude them- 

 selves constantly on the observer as entities usually distinctive 

 in appearance*'. Such forms in certain cases may owe their 

 peculiarities to the action of special influences during individ- 

 ual development, but this explanation, in my opinion, will not 

 usually suffice. When certain distinct varieties of a given 

 species recur again and again in material from widely separated 

 regions of diverse environmental nature, it would seem suffici- 

 ently clear that some factor of genetic or perhaps evolutionary 

 significance is involved, since under such conditions the chance 

 of exact duplication of ontogenetic environment is negligible. 

 Even if it were shown that gross similarity in environing influ- 

 ences, such as a season relatively hot, cold, wet, or dry, could re- 

 sult in a preponderating number of individuals belonging to a 

 certain variety, we would still feel impelled to seek some genetic 

 factor which such conditions might call into activity, in order to 

 account for the detailed nature and general uniformity of the 

 .adult varietal characters thus produced. The taxonomist fails 

 in his duty if he avoids the responsibility of discriminating and 

 naming these forms, since in this way only may definite data on 

 distribution and seasons be made known for each, and the stu- 

 dent of experimental genetics should not neglect them, since 

 in these forms of Hemiptera he has definite variations pro- 

 duced under natural conditions, and he is therefore free from 

 the justifiable suspicion that laboratory conditions — domestica- 

 tion, so to speak — may have had some untoward influence in 

 the matter. At least he will be able to collect in the field speci- 

 mens to ser\'e as checks in the consideration of the product 

 of his breeding cages, an advantage which cannot be claimed 



' Cf. my Hem. Notes, Psyche, Vol. 23, 1918. pp. 64-65. 



