BULLETIN OF THE BROOKLYN ENT SOU 



Taking- the divisions below the genus, we have the following ideas: 



1. A species is a certain form breeding true to itself in its own 

 limitations, and which, however variable with regard to itself, does 

 not in any place or under any circumstances, in the outreach of its 

 Variations, overlap any other form and become its counterpart. 



2. A variety is a form of a species, connected with it by intergra- 

 dations, but which, under certain circumstances, exists as a constant 

 form, to the exclusion, or almost entire exclusion, of any other form 

 of the species, or which, without intergrad.es, exists permanently un- 

 der any circumstances, yet by breeding is known to be connected by 

 direct descent with the other forms. A permanent variety, breeding 

 true to itself only, becomes a species. 



3. When, in the same locality, certain forms of the same species 

 exist connected by intergrades, all the forms are, as much as the type- 

 form, valid representatives of the species. As a matter of convenience 

 and explicitness, it is well to have names for forms widely varying 

 from the type-form; but they, at best, express sub-rarieties, and, in 

 cataloguing, must be considered synonymns only of the original name. 

 In this matter we would not be quite as radical as some coleopterists 

 who throw out names which designate forms of the same species, no 

 matter how different to ordinary observation, and will not have them 

 used at all* ; yet, if synonomy is strictly carried out, these follow the 

 only rule which can be defended as logical. A sub-variety, existing 

 to the exclusion of other forms, becomes a variety. 



4. An aberration is a form of a species separate from the normal 

 form, without intergrades, and appearing without permanency. A 

 permanent aberration becomes a variety or species. 



5. Determination ought to cover the whole history of the insect. 

 G. Well-marked forms must be considered valid species until, by 



breeding or intergrades, they are connected with other forms so 

 closely as to allow no reasonable doubt of their identity. 



7. Species may be very close to each other. 



8. Varieties and sub-varieties may be very widely separated. 



9. A single specimen, or single specimens at distant intervals of 

 time, taken in a locality which for years has been pretty thorough- 

 ly collected over, and differing from described species, should be 

 cautiously adjudged a new species ; for, if allied to a species com- 

 mon in the locality, it is almost surely a variation of that species ; 

 and, if widely separated from any species taken there, is yet likely to 

 be a variety or aberration of some species well known. 



* Dr. Packard, in his "Geometric! Moths," lias, we see. adopted this rule. 



