88 BEITISH TYEOGLYPHID^E. 



their small nuclei are central surrounded by a small 

 space for secretion. The secretion of the globular 

 gland is rich in small, dust-like, highly refractive 

 particles ; that of the crescent-shaped gland is homo- 

 geneous and like white of egg. 



I am not aware that any other author has described 



t/ 



the c? accessory glands of the Tyroglyphida3. 



The Penis and its associated sclerites vary so greatly 

 in different species that Nalepa suggested that they 

 would form a good means of distinguishing species ; 

 this as to the penis itself will be seen not only from 

 PI. B, figs. 3 5, but also from the various figures of 

 the organ on the plates depicting the respective 

 species. In the penis however the great diversity of 

 form and position is united to a correspondence with a 

 general scheme or type which runs through the whole ; 

 the associated sclerites however vary not only as to 

 matters of form and detail, but also as to the entire 

 principle upon which they are constructed. 



The penis when at rest lies in the external genital 

 aperture of the male (PI. B, fig. 3), or it may be with- 

 drawn within the body. In Glycyphagus platygaster it 

 has a spoon-shaped bulb at its proximal end ; I call it 

 spoon-shaped for want of a better name, but it is too 

 deep in proportion to its breadth to agree in form 

 with any ordinary spoon ; the convex side of the 

 spoon is downward, and the bulb looks like a closed 

 vessel when it is viewed from the ventral aspect ; the 

 upper side of the bulb is however quite open without 

 anything to cover it in, and it is into this that the 

 sperm and the secretions of the accessory glands are 

 discharged by the ductus ejaculatorius. At the distal 

 end of the bulb the organ suddenly narrows and 

 becomes a closed tube, and continues to be so to its 

 distal termination. This tube tapers more gradually 

 when seen from the side than when seen from the 

 ventral surface ; it is also strongly curved, the curve 

 being upward when the organ is at rest, more forward 

 when it is erected (PL B, fig. 5, pe). On the external 



