CLASSIFICATION OF THE TYKOGLYPHID^E. 39 



hairs, which feather the main ones, are extremely 

 minute and fine. Still there are excellent points in 

 this simple classification, as might be expected in Meg- 

 nin's work, and it is the foundation of much of our 

 present arrangement. 



Professor Giovani Canestrini in 1888 pub- 

 lished two works on the Tyroglyphida3, viz. ' I Tiro- 

 glifidi, studio critico,' and vol. iii (containing the Tyro- 

 glyphidas) of his c Prospetto dell' Acarofauna italiana.' 

 The same classification of the family is contained in 

 each of these ; the following is a translation of it : 



ANALYTICAL KEY FOR THE CLASSIFICATION OF G-ENEEA. 



1. Anal suckers exist in the male . . . .7 

 Such suckers are absent . . . .2 



2. Aberrant suckers exist in botli sexes ; palpi furnished with a 



cliitinous membrane and therefore dilated 1 Histiostoma, Kr. 

 Without suoh suckers ; palpi normal . . .3 



3. Migratory nymph homopial ; living oil mammals 2 Homopus, K. 

 Migratory nymph not homopial or not existing . . 4 



4. Tarsal claw rudimentary . . 3 Glycyphagus, Her. 

 Tarsal claw distinct . . . . .5 



5. Genital suckers absent in both sexes ; vulva situated behind 



the epimera of the second pair of legs . 4 Hericia, On. 



Genital suckers exist in at least one of the sexes . . 



6. Both sexes possess genital suckers . 5 Phycobius, On. 

 Genital suckers exist only in the female . 6 Trichutarsus, Cn. 



7. Male provided with foliaceous appendages at the posterior 



extremity of the body . . 7 Histiogaster, Berl. 



No such foliaceous appendages . . . .8 



8. No furrow between cephalothorax and abdomen 



8 Chortoglyphus, Ber). 

 Such a furrow exists , . . . .9 



9. First pair of legs of the male thickened and spurred 



9 Aleurobius, Cn. 



First pair of le^s normal . . . .10 



30. Tarsi long, without suckers; no dimorphism of the male 



10 Tyrof/hjphus, Lat. 

 Tarsi short, without suckers, male dimorphic Rhizoglyphus, Clap. 



To say that this classification is by Professor Canes- 

 trini is equivalent to saying that it is a valuable one ; 

 but yet I cannot quite agree with all of it. It seems 

 to me rather technical, and hardly to bring the main 

 structural differences into sufficient prominence. It 



