56 Mr. S. S. Saunders's Description of 



entire pith has been removed by some former constructor, and 

 the ordinary proceedings of the Trypoxylon as aforesaid, equally 

 applies to the Hylcei, whose diminutive tunnels, perforating and 

 often winding through the pith, essentially differ from any made 

 by an Osmia or an Odynerus. 



In concluding these observations upon the Strepsiptera, and the 

 insects on which they parasitically subsist, — a subject wherewith 

 the name of our honorary President is indissolubly associated, — 

 I cannot better dispose of the specimens illustrative of this com- 

 munication than by consigning them to the Museum of this 

 Society. 



Diagnosis of the Specimens. 



1. Hylecthrus Rubi, $. (PL VIII. fig. 1), with its foster-parent 



Hylceus versicolor $ . 



2. Bred-specimens of the Hylecthrus Rubi $. (PI. VIII. fig. 2a — 



2d), with Hylceus rubicola, $ and 2 • 



3. Cephalo-thorax of hexapod- bearing female (PI. VIII. fig. 2e), 



with some of her progeny. 



4. Corneous operculum of pupa-case of the male (PI. VIII. fig. lh). 



5. Hylecthrus Quercus $. 



6. Hylceus gibbus 2 , with exuviae of the preceding. 



Briars. 



A. Briar exhibiting the normal construction of the cells of Hylceus 



versicolor and rubicola, in galleries perforating the pith, — 

 often in a double or triple parallel series, as in this instance. 



B. Briar-snag excavated by an Osmia, whose pupa-cases remain 



below; the upper portion being occupied by Hylcei, and 

 the intervening space having contained some liquid acidulous 

 honey. 



B. 1. Specimen of the Osmia. 



B. 2. Pupa of the same in spirits. 



C. Briar containing the mud-constructed cells of a large Odynerus, 



with others of Hylceus superposed, and arranged obliquely. 



C. 1. Hylceus reared from this briar. 

 C. 2. Nymph of the same in spirits. 



D. Briar occupied in part by Cemonus unicolor, with the tapestried 



cells of Hylceus above ; the occupants of the latter having 

 been destroyed when the Cemoni effected their exit. 



