Vol.XXv] ENTOMOLOGICAL NEWS 15 



4. Though transitionals obscure limiting lines in dead ma- 

 terial, species exist in young stocks and the actual limits of 

 each are such as it makes for itself by the general interbreed- 

 ing of its constituents under normal conditions. 



5. The normal self-observed limits of species in nature 

 among young stocks must be worked out on the merits of each 

 case by the study of living material through all its stages with 

 relation to its environment. 



6. As a basis for this work all recognizable forms in young 

 stocks must be described, named and regarded as tentative 

 species until their status is finally determined. 



7. All recognizable forms in young stocks demand a name 

 and final place in the taxonomic system down to race rank, and 

 none should be lost sight of by lumping of names. 



8. Isolated or aberrant transitionals need no distinctive 

 name, but as a matter of record they should be descriptively 

 differentiated from that form which they most closely approach. 



9. It follows that the describing and naming of forms in 

 young stocks should be based on as large series as possible. 



Notes on the Thoracic Sclerites of Winged Insects.* 

 By G. C. CRAMPTON, Ph.D. 



.(Plate III.) 



As used by most anatomists, the term dorsum is applied to 

 the entire upper or dorsal surface of an insect's body ; the en- 

 tire side, or lateral portion of the body is termed the I at us; 

 and the entire lower or ventral surface is termed the venter. 

 To avoid confusion, these terms should be used in this sense 

 alone. 



The entire dorsal region of each segment (i. e. the more 

 membranous, as well as the more strongly chitinized portions 

 of the body wall) is termed the tergnm, or not um; the entire 

 lateral region of each segment is termed the plcnron (both 

 flanks being termed the pleura] ; and the entire ventral region 



*Contribution from the Entomological Laboratory of the Massachu- 

 setts Agricultural College, Amherst, Mass. 



