228 Mr. F. Muir's Notes on the Ontogeny and Morphology 



and have no phylogenetic significance no entomologist of 

 any standing will deny. 



Whilst recognising the great interest and value of much 

 of the work in comparative morphology of "recent years, I 

 cannot help entering a protest against the methods of 

 some of the workers who have made a fetish of homology. 

 Having selected what they consider to be a generalised form 

 they proceed to delineate and name each sclerite, and then 

 set themselves to discover similar sclerites in other more 

 specialised types. It is under the influence of this idea that 

 certain workers profess to find portions of the tenth 

 tergite and sternite in the armature and chitinisations on 

 the internal sac. If they would remember that an insect 

 is a double membranous tube with a number of invagina- 

 tions and evaginations, certain areas of which become more 

 or less stiffened by the deposition of chitin, and that the 

 male genitalia of Coleoptera is a tubular evagination arising 

 from a median position between the ninth and tenth 

 abdominal sternites, they might recognise the improbability, 

 or even the impossibility, of a tergite or portion of a tergite 

 becoming attached to the apex of a tubular organ in such 

 a situation. 



My thanks are due to Dr. David Sharp for much interest- 

 ing information, and for placing at my disposal his large 

 collection of dissections made since we published our joint 

 paper on this subject in 1912. 



Explanation op Plate X. 

 Figures. 



No. 1. Rhabdocnemis obscura (Boisd.). — Early stage of male genitalia 



in the pupa. Cm, wall of the genital invagination; tf, 



tegminal fold; ml + is, median lobe and internal sac; 



fu, the functional orifice will eventually open here ; 



ej, ejaculatory duct; m, embryonic muscles between the 



eurazygos and the stenazygos. 

 X<>. 2. The same about half developed. 

 Xo. 3. The same fully developed or nearly so. 

 No. 4. Coccinella repanda. — Early stage of male genitalia in the 



pupa. 

 No. 5. The same three-fourths developed. 

 No. »>. Carpophilw humeralis.—Jfevly stage of male genitalia in 



the pupa. 

 Xo. 7. The same nearly fully developed. 



o. 8. Dermestis, sp., showing the nine abdominal segments and 

 X the aedeagus. 



