268 



an undeveloped stage of that species. In order to prove this, however, 

 it would be necessary to rear the nymph to the adult state. Dr. C. F. 

 George has recently recorded this mite from Lincolnshire in England. 



The following list contains all the Irish species of Hydrachna 

 which have been brought to light. H. paludosa Thon, found in the 

 Shannon at Lough Ree, has not been previously recorded from the 

 British Isles. 



Hydrachna paludosa Thon. Hydrachna maculi/era Piersig. 



H. scutata Piersig. H. dissimilis n. sp. 



H. biscutata Thor. H. conjecta Koenike. 



H. incisa n. sp. H. globosa de Geer. 



H. Leegei Koenike. H. sp. (nymph.) 



Early last October I found near Dublin an Arrhenurus of the sub- 

 genus Megalurus which seemed to agree in certain characters with the 

 recently described A. adnatus Koen. 2 . On sending drawings to Dr. 

 Koenike, however, he says it is not adnatus, and as it does not agree 

 sufficiently with any of the known species, I venture to describe it 

 under the name of 



4) Arrhenurus Fr eemani n. sp. 3 . 



Male: Length, including appendage, 1,44 mm, breadth 0,78 mm. 

 Colour green, tending to yellow on the coecal area, and marked with 

 reddish brown blotches. Legs and palps pale green, the former have 

 the terminal segments yellowish. The main body is shaped much as 

 in A. conicus Piersig, but it is a- larger mite with the anterior margin 

 more rounded. Dorsal impressed line sinuate in front inclosing four 

 circular papillae, and terminating on the underside of the tail. Appen- 

 dage a little more than half the length of the main body, rather deeply 

 constricted at the base, suddenly widened to its greatest breadth 

 (0,43 mm) at the anterior third, and thence gradually narrowed to the 

 side angles. The latter bear two prominences which slightly over- 

 reach the outline of the sides; distal margin noticeably produced in 

 the centre, terminating in two more prominences separated by a 

 shallow indenture. At the end of the dorsal swelling of the appendage 

 there is a mark the exact details of which it is difficult to see clearly, 

 but it is shaped somewhat as in fig. 6. Near the middle of the de- 

 pression at the end of the appendage there is a small conical papilla. 

 Viewed from the side an irregularly shaped hyaline process can be 



2 Zool. Anz., Vol. XXV. 1902. p. 615. 



3 Named after my friend D. Freeman, M. A., M. B., the first worker to 

 interest himself in the Irish Hydrachnid fauna. 



