°jg g j Correspondence. 121 



era, and says that I have merged all the subgenera recognized by Hellmayr in 

 his recent excellent monograph of the Paridse in Parus and that " my treat- 

 ment of this and allied families is far less satisfactory, and less consistent 

 and rational, than the recent revision of these groups by Hellmayr." Need- 

 less to say J am not of the same opinion. The reviewer does not explain in 

 which way my treatment is inferior to that of Hellmayr. The one point 

 he objects to is, that I have no use for subgenera. This, however, is a matter 

 of opinion, and the omission of subgenera does not make a work inferior. In 

 my opinion subgenera are an unnecessary impediment. If a number of 

 species is to be grouped into various sections, this is better done under name- 

 less headings, such as "Blue Tits," "Grey Tits" etc., or A, B, C but if a 

 name is given to these sections — which of course have not generic value, 

 or else they would be recognized as genera — it leads to some persons adopt- 

 ing these names, others not, and some even using both names! This incon- 

 sistent treatment may be seen every day. Every student of palsearctic 

 Paridae must come to the conclusion, that the genus Parus, as limited by 

 me, cannot be split into full genera: nevertheless a "subgenus" Cyanistes 

 (among others) is recognized by some authors. What is the result? Most 

 authors call the "Blue Titmouse," the type of the "subgenus" Cyanistes 

 as usual Parus coeruleus, others make use of the subgeneric name and call 

 it Cyanistes ccerukus, others again call it Parus (Cyanistes) cceruleus. All 

 this is avoided by not giving a name to the so-called subgenera, regarding 

 them merely as sections, tribes or subdivisions and calling them group 

 A, B, C, etc., or the Black-and-white group, group with yellow or without 

 yellow, etc. I fail to see entirely for what purpose subgenera are recog- 

 nized and named, if no use is made of their names; on the other hand it is 

 not scientific to treat them as genera, because, as in the present case, they 

 cannot be separated by any constant characters, and I object to using both 

 names, i. e. that of the genus and subgenus, because it makes our nomen- 

 clatorial apparatus unnecessarily cumbersome. Ergo: my most decided 

 opinion is that "subgenera" are unnecessary and undesirable. 



Except in the absence of subgenera my work differs from that of Mr. 

 Hellmayr in the following points: I have combined still more allied forms 

 as subspecies, added some formerly unknown forms and corrected a few 

 errors. I do not deny my very strong tendency to combine allied forms as 

 subspecies. My reviewer says that I have done this " sometimes apparently 

 without satisfactory reasons therefor, as where Parus sclateri of Mexico is 

 made a subspecies of Parus palustris, although separated geographically 

 by thousands of miles. ..." This treatment is, in my opinion, only appar- 

 ently, but not really "unsatisfactory." My critic has never seen Parus 

 dejcani nor Parus hypermelama, or he might more likely have said that they 

 were indistinguishable from Parus sclateri, and P. dejeani and hypermelama 

 are in my opinion connected by intermediate forms with palustris, and there- 

 fore subspecies. All this I have carefully explained in my book. These 

 are difficult forms and difficult questions, to the study of which I have de- 

 voted the best part of a winter, with a material never seen before by one 



