Charakteristik der Gattungen der Notacanthcn. 377 



one, aquainted with Actina tlbialis knows that in tliis species tbe 

 third vein, issuing from the discal cell, varies in lengtli. In a specimen 

 whicli I liave before me, that vein is rudimentary on the left wing; on 

 the right it is merely abbreviated and reaches the middle of the distance 

 between the diseal cell and the margin. A much more important and 

 available diflference between the two genera consists in the structure 

 of the palpi , well developed in Actina and rudimentary in Beris; but 

 this character is not noticed in Dr. B.'s paper. 



In the same way the remarkable emargination of the eyes, a very 

 striking character of Rhachicerus, is not mentioned at all. 



I do not think therefore that the title of the paper: Characte- 

 rization etc. is justified by its contents. — That the characters of 

 Arthropeas and Rhachicerus, as introduced in the dichotomic table, are 

 the reverse of what they actually are, has been shown above; also that 

 the characters of Macroceromys, Hermetia, Exochostoma and Anacan- 

 thella are inaccuratelj^ described. 



Another defect of Dr. B's table is that the genera known to tbe 

 author by sight, are not clearly discriminated from those which he 

 knows merely from descriptions. Tor instance he speaks as jpositively 

 about Exochostoma and Thorasena, as if he had specimens in view; 

 while in reality, as I have shown, he has not even read Macquart's 

 descriptions and has merely borrowed bis facts from that author's very 

 inferior plates. Such defects, once discovered spread a haze of doubt 

 over the whole paper, and render it unsatisfactory as a source of po- 

 sitive information. 



A third defect is that references are almost altogether omitted. 

 Papers of this kind are not written for the few who know all about 

 the subject in question, but for the raany who know little or no- 

 thing. For readers of the latter class Dr. B.'s paper will be füll of 

 puzzles, and they will uselessly consume a great deal of time in 

 hunting for the references which the author should have given. For 

 instance , why not add the references to the list of more than one 

 hundred genera, placed at the end of the paper. (The list is otherwise 

 complete and Hirtea Scop. is the only name I miss in it.) The fi'equent 

 quotation of references, as I know from experience, is useful in more than 

 one way; the author himself in verifying them, often finds occasion to 

 rectify his Statements. If Dr. B. had used this precaution he would 

 have avoided good many of the mistakes which he committed. 



I regret very much to have been obliged, in this instance, to cri- 

 ticize one for whom I have the profoundest esteem as a man, as well 

 as a zealous and talented entomologist; that in adopting this course, 

 I had no other aim in view but the interest of truth, I need scarcely add. 



