Dr. David Sharp's Studies in Rhynchophora. 215 



case in the forms I have mentioned as having the tegmen 

 in the shape of an incomplete ring. 



Although I wish to avoid at present all points of 

 ultra-morphology, yet I think it is only proper to remark 

 that the functions of the tegmen as part of a mechanism 

 are complex, and until they are ascertained — at any rate 

 to a certain extent — we must merely make use of the fact 

 of constancy or inconstancy, for taxonomical purposes. 

 Y.'i'lioeff (Arch. f. Naturges, 62) treats the " (label " as 

 " Paramerenreste." 



So much doubt exists as to the ultra-morphology of 

 " parameres " in Coleoptera, that the term has been alto- 

 gether abandoned by Muir and myself. And this not 

 because the term is a bad one, but because of the great 

 amount of theory that is associated with it. As an in- 

 stance of this T may mention thai Verhoeff in the memoir 

 cited states (p. 139) that " the parameres of male Coleoptera 

 are the true genital appendages." From what follows it 

 a | (pears that he means In' this that the median lobe is the 

 equivalent of a body segment, or somite, and that parameres 

 are the equivalents of appendages of a somite (i. e. of legs, 

 or of palpi). Such a view is almost or quite metaphysical, 

 and I hope that I may be doing an injustice to Verhoeff 

 in believing that is what he is promulgating. 



In Rhynckophora the structure of the tegmen and the 

 condition of the membranous areas immediately adjoining- 

 it are complex and varied, so that a special memoir on this 

 part will have to be prepared. I am not able to give any 

 information of a thorough nature on the matter, and in 

 some forms where the tegmen is complex (Brachycerus, 

 Microcerus, Anthribidae, and others) I anticipate that a 

 knowledge of the development will be essential, for there 

 appear in some cases to be folds that have become solidified 

 by chitinous exudation. 



The tegmen is placed at a part of the tube where, accord- 

 ing to observations of F. Muir, a primary invagination 

 occurs in development. This of itself must give rise to 

 folding or doubling of the walls of the tube at this spot, 

 and this is probably bhe real starting-point of the tegminal 

 complications. 



The Median Lobe. 



Near or at the tegmen there exists a turn down of the 

 membrane, which results in the connection of the mem- 



