237 



borus Oudemans 1902). It is characterized by haviag, most pro- 

 bably, no free hypopus; by haviag a demarcation between ce- 

 phalothorax and abdomen on the usual place; and by having 

 feather-like or flat hairs on the body. It has Acarus plumiger 

 Koch as type, and contains the following species : 



1 (3) Ctenoglyphus plumiger C. L. Koch, 1836. 



2 (11) » palmifer Fumouze et Robin, 1867. 



3 (19) ■» canestrinii Armanelli, 1887. 



4 (22) » pterophorus Berlese, 1891. 



Fourthly the genus Glycyphagus Hering, 1838 (not 1835, for 

 Hering presented his treatise to the Caes. Leop. Car. Academy 

 in 1835, but it was not published before 1838). It has Glycy- 

 phagus prunorum Hering as type. Unfortunately this species is 

 not found again since that year. It is a typical one, for the fe- 

 male genital aperture is round, lies in the middle of the ventral 

 side, and the epimera II are very long and reach the aperture 

 (suppose that Hering's drawing be correct, which we may not 

 assert of his representations of Tyroglyphus stro (L.)), thus resem- 

 bling in these respects Lentungula algivorans Michael ; so that Gly- 

 cyphagus prunorum Hering stands alone among the other mern- 

 bers of the genus and most probably, if found again, will prove 

 to be quite another type as the common Gl. domesticus (de Geer) 

 and allied congeners. Cephalothorax and abdomen fused. Thus: 



1 (4) Glycyphagus prunorum Hering, 1838. 



Another species, Acarus hyalinus of Koch, has a demarcation 

 between cephalothorax and abdomen on the usual place, and a 

 shape like that of Tydeus (Thrombidiidae), or of the nympha of 

 Aleurobius farinae (L.), only two small apparently smooth hairs 

 on each shoulder, and 4 ditto on the posterior edge. In these 

 characteristics it stands alone. Therefore: 



1 (5) Glycyphagus hyalinus (0. L. Koch), 1841. 



Another species is Gl. fuscus Oudemans. It is brown, appa- 

 rently not weak, polished; has small curved, smooth hairs; and 

 all the coxal plates, even those of the maxillae, fused-to one 

 single, polished, hard plate ; the genital opening of the male lies 



