702 FAUNA HAWAIIENSIS 



ACARINA. 



V'' 





\> 



^ -' By N. D. F. Pearce, M.A. 



General remarks on the collection must necessarily be brief, as the small 

 number of species represented in it (nine, besides a few specimens that cannot be 

 certainly identified) is pretty sure evidence that the collection cannot be considered 

 typical of this branch of the Hawaiian fauna. In Britain some hundred species have 

 been identified and described, and a very simple method of collection (merely shaking 

 or preferably slowly drying a few handfuls of moss) will generally produce an enormous 

 number of individuals. But unless a collector's attention has been specially directed to 

 the group, their small size will inevitably lead him to overlook them. I do not know 

 by what method these specimens were collected, and am only surprised that so many 

 were obtained. 



Six of these species are well known as British ; or perhaps it would be better to 

 say that they differ so little as to be practically indistinguishable. It must be remem- 

 bered that we can only rely on external characteristics in a case like the present, and 

 even when dealing with recent material the internal anatomy of such minute creatures 

 is almost unobservable. 



Of the new species the most interesting is one belonging to the genus Tegeocranus. 

 Though some sjaecies of this genus are by no means rare in Britain, it is certainly one 

 of the less common genera ; thus it has never to my knowledge occurred in Cambridge- 

 shire (although this county has been considerably searched for Oribatidae) and I have 

 but seldom received it from abroad. It appears to me to be a moribund genus. It is 

 of special interest from the extraordinary forms assumed in the immature stages, forms 

 utterly different not only from the adult, but, with an exception or two, from anything 

 acarological, and paralleled only by the remarkable nymphal form of Lciosoma palini- 

 cincttim : perhaps too among the Tyroglyphidae by the somewhat uncommon Glyciphagi, 

 p/niiiifcr, palmijcr and canestrinii. 



I now proceed to a description of the contained genera and species. 



Fam. ORIBATIDAE. 



Subfam. PTEROGASTERINAE. 



Oribata Latreille. 



(i) Oribata globitla Nic. 



Twenty-one specimens, A very widely distributed species, occurring in collections 

 nearly everywhere. 1 cannot see that these differ appreciably from British types. 

 (656 X is a nymph of this species, probably.) 



Hab. Hawaii, Lanai. — Hawaii ; Kilauea, Lanai ; Halepaakai. 



