232 BRITISH TYEOGLYPHIM:. 



instead of being provided with suckers to hold on to 

 smooth surfaces like most other Hypopi, then the 

 genus Dermacarus might well be revived ; but to be at 

 all satisfactory the definition of the genera, whatever 

 it may be, must be such as to place (including foreign 

 species) palmifer, pteroptus, ornatus, plumiger, Canes- 

 trinii, perigrinans, spinipes, domes ticus, and intermedius 

 in one genus, and dispar, platygaster, Cramer i, sciuri- 

 nus, and probably arvicolae and hypudari, if both be real 

 species, in the other. 



GLYCYPHAGUS. 



Tyroglyphidse with the ambulacra of all legs sessile ; 

 caroncle usually more developed than the claw ; with 

 chelate mandibles ; with the bursa copulatrix of the 

 female forming a tubular projection in the centre of 

 the posterior end of the abdomen. With or without a 

 division between cephalothorax and abdomen ; with a 

 cuticle usually more or less rough, never polished. 

 With considerable, rarely extreme, sexual dimorphism. 

 Dorsal hairs usually pectinated or plumose, or trans- 

 formed into foliaceous scales or into spines. Without 

 anal suckers. Hypopial stages, as far as at present 

 known, either quite rudimentary and not functional, or 

 else active and homopial. 



This genus probably contains all the most beautiful, 

 and many of the most interesting, species in the family ; 

 many of them are great destroyers of human stores of 

 foodstuffs and other dried vegetable and animal matters. 

 Few more beautiful microscopic objects can be seen 

 than a good female specimen of Glycyphagus Canestrinii, 

 properly shown with black-ground illumination. The 

 question of sexual dimorphism in the genus is also 

 interesting, because in all known species except G. 

 dispar the male, although very different from the 

 female, is sufficiently like her to cause any observer to 



