Clare Island Survey — Acarinida. 39 85 



Family UROPODIDAE. 

 Cilliba cassidea (Herm.). 



Clare Island, in moss, March; Achill Island $ and ? in moss and under 

 bark, September and November ; Westport district, adults and nymphs in 

 August. 



Berlese describes two forms of this species which he separates as 

 follows : — 



" Dorsum glaberrimum, scutum genitale foeminae, nitidum 750^. long . . . 

 Discopoma cassidea G. et R. Can. (Herm.). 



" Dorsum setosum, scutum genitale foeminae punctulatum. Ad 460^. long. 

 D. cassidea var. minor Berl." (2) 



An examination of numerous Irish specimens shows the presence of hairs 

 on the dorsum, and the female genital shield is distinctly punctulate. In 

 the matter of size, however, they agree with the typical form, measuring from 

 744^1 to 921,u in length. Both sexes vary equally in size. Possibly these 

 specimens may be referable to a large form of the species. 



A few of the nymphae homeomorphae were also found. In these the broad 

 marginal part of the body is imperfectly chitinized on the ventral side, 

 forming three pairs of plates. The second segment of the first pair of legs is 

 without the distal spur which is always present in the adult. 



Distribution. — Germany (Koch) ; Italy (Berlese) ; Holland (Oudemans, 

 who records both the type form and the variety minor Berl.). 



There is a difference of opinion amongst acarologists concerning the use 

 of the generic names Cilliba, von Heyden and Discopoma, Canestrini for the 

 preceding species (cassidea Herm.), a question concerning the validity of 

 von Heyden's genera. Mr. Michael has dealt with the subject at length 

 (49, p. 295) giving his reasons for the revival of certain of von Heyden's 

 genera including Cilliba. Until the appearance of his valuable paper " Acari 

 Mirmecofili," Berlese had consistently used Discopoma to include cassidea 

 Herm. In that paper, however, he states that there is sufficient reason for 

 the revival of ( illiba, with cassidea as the type, as indicated by von Heyden, 

 thus agreeing with Michael's use of this name, while Kramer's " Uropoda 

 splendida " is selected as the type of Discopoma. Berlese remarks " il 

 genere Discopoma di G. et R. Canestrini, sembra avere realmente per tipo la 

 D. splendid//, almeno questa e la prima specie (sotto il nome D. clypeata), 

 che i detti Autori illustrano." It is fortunate if, for this reason, both of 

 these generic names can be preserved. 



k.i.a. psoc, vol, xxxi. M 39 



