ACARINA FROM THE JUAN FERNANDEZ ISLANDS 57 7 



this species the type of a new subgenus, Phyllhermannia and as in the case 

 of EutegcEUS without giving any generic diagnosis. It is therefore left to later 

 investigators to find out, whether the presence of leaf-shaped bristles is asso- 

 ciated with other features and thus of generic value. For this purpose I have 

 examined material of H. reticulata Thorell and the present species and, as 

 a matter of fact, discovered some differences. It is, however, impossible to 

 know whether these also occur in P. phyllophora, because one of them cannot 

 be seen without dissecting the specimens and MlCHAEL had only one specimen 

 to his disposal, which he did not dissect. On the whole my species agrees in 

 so many respects with MlCHAELs that it seems reasonable to suppose that it 

 agrees also in these. 



A comparison with H. reticiilata and P. dentata n. sp. reveals the follow- 

 ing differences. In the former the border between the propodosoma and hys- 

 terosoma is strongly chitinized and immovable. In P. dentata there is a narrow 

 transverse fold of weak chitin between them and the posterolateral edge of 

 the propodosoma has a sharp tooth, opposite to which there is a similar tooth 

 below the anterior margin of the dorsal shield (fig. 46). 



This feature is indeed so difficult to see if the specimen is not dissected, 

 that even such a careful investigator as MICHAEL failed to see it in Carabodes 

 elongatus, which now is the type of the genus Odontocepheus, which is charac- 

 terized through this feature. 



Further the epimera I — III of P. dentata, and also of P. phyllophora, do 

 not form a right angle with the sternum as is the case in Hermannia but run 

 obliquely forwards. 



In both P. dentata and P. phyllophora there is a transverse fold between 

 epimera IV and the genital aperture. This fold is absent in Hermannia. In 

 P. dentata the hind margin of epimera IV is thickened to a ridge, the median 

 half of which has 3—4 rounded, knoblike teeth. We do not know whether 

 this raised ridge is a generic character, as I believe. It seems incon- 

 ceivable that if they were present in P. phyllophora MlCHAEL would not have 

 noticed them. 



But it is evident that M. examined a very dark specimen of his species, 

 which he did not dissect, nor treat in any way to make it transparent, nor 

 looked at against a dark field illuminator. Else he would have seen the inter- 

 lamellar and lamellar hairs, which he failed to do. It is therefore very likely 

 that his species has the posterior margin of epimera IV developed as a similar, 

 dentate ridge. 



On the whole it is in our present stage of knowledge not quite easy to 

 define Phyllhermannia from Hermannia, and we must await the discovery of 

 more forms until this can be definitely settled. The following diagnosis is 

 therefore tentative. 



Diagnosis: General shape the same as in Hermannia, but texture 

 either smooth or finely punctured. Dorsal hairs of hysterosoma, 

 lamellar and interlamellar hairs lanceolate, leaf-shaped and hairy. 

 Postero-lateral angles of propodosoma with a sharp tooth, opposite 

 to a similar tooth on anterior margin of hysterosoma. Epimera I — 

 III not running at right angles with sternum but directed obliquely 



