( 107 ) 

 COERESPONDENCE. 



On some New Paeasites. 



To the Editor of the ' Monthly Microscopical Journnl.'' 



July 8, 1871. 



Dear Sir, — May I be permitted to draw attention to some para- 

 sites named and figured in the July number of the ' Monthly Micro- 

 scopical Journal,' by Mr. T. Graham Ponton, F.Z.S. 



Having been engaged in collecting and studying these insects 

 for some years, I am well aware of the difficulty of making out the 

 genera and species froiu dried or mounted specimens, and of the con- 

 sequent necessity of carefully exact drawing in the illustration of 

 these minute forms. 



Without entering upon the many structural inaccuracies with 

 which Mr. Ponton's plate is literally crowded,* I wish simply to 

 notice two errors, which, if uncorrected, are enough to throw the whole 

 subject into confusion. 



In Fig. 3, a presumed new species of the sub-genus Docophorus, 

 the legs end in single claws, — whereas all the species of Docoj)horus 

 and the allied sub-genera have a pair of claws proceeding from their 

 short two-jointed tarsi. 



The Trichodectes, Fig. 4, is figui'ed with double claws ; the chief 

 character of the genus being that they are single. In fact, all the 

 species of the obsolete order " Anoplura," which infest mammals, 

 have single tarsal claws. 



A Trichodectes with double claws is as absurd to anyone familiar 

 with the genus as a horse with cloven feet. 



I remain, dear Sir, yours faithfully, 



H. C. ElCHTER. 



The New Metallic Covebed Glass Chimney. 



To the Editor of the ' Monthly Microscopical Journal.' 



Sir, — Some short time since it occurred to me that a very useful 

 addition to our microscopic appliances might be made by having the 

 ordinary glass chimney silvered on the outside, and covered with some 

 protective substance. 



I had one made on this principle, and showed it to Mr. Swift, 



* [It is almost unnecessary to observe that the author is alone to blame. 

 Proofs of the plate were sent to him, and his corrections were carefully carried 

 out : the original drawings were such as to render the artist's task one of no 

 small difficulty ; but for the points referred to by Mr. Richter, Mr. Ponton is 

 solely to blame.— Ed. ' M. M. J.'] 



VOL. VI. I 



