388 MR. J. N. HALBERT : NOTES ON ACAEI, 
the front margin of the body, separated from edge of ventral plate at the 
side and end margins by a rather broad band of soft, striated cuticle, which 
contains about five pairs of pores. On the dorsal plate is a double row of 
similar pores, near each of which is a fine hair. Eyes placed at each corner 
of the front margin on the dorsal outline of the body. Frontal bristles very 
short (PI. 22. fig. 29 a). Epimeral region much as in D. elongata, except 
the outer border of the fourth pair, instead of being absent, is indistinctly 
defined (PI. 22. fig. 29 &). The genital plate is shorter (length 132 /i, 
breadth 100 yti). Length of maxillary plate to tip of rostrum 120 ;tA. Palps 
very stout, the second segment broader than the legs (breadth in dorsal view 
49 yti): on its inner ventral margin is a low, rounded prominence and a strong- 
hair as in the type-species. Inner distal angle of the fourth segment pro- 
duced in the form of a strong triangular tooth, and beside this is a smaller 
tooth, both bearing- fine hairs ; near the dorsal line of the palps are a few 
short spines (PI. 22. fig. 29 c). Legs of moderate length, stout, armed with 
short spines and without swimming-hairs ; the lengths are about 240 ii, 
374 /li, 330 //,, and 410 /x. 
Locality. A single specimen found amongst sjjhagnuir, moss collected on Ott 
Mountain, in the Mourne Mountains, in May by Mrs. R. F. Seharff. 
Ljania bipapillata, Sig Thor, has been found in the River Dodder, near 
Dublin, in November ; in the River Dorgle, at Powerscourt, and in the stream 
flowing between the lakes at Glendalongh, Co. Wicklow, in April. The colour 
of living specimens is pale yellow with brownish markings. Megapus gibheri- 
palpis, Piersig (40), occurs in streams on the Dublin Mountains at Kilkee and 
Kilmashogue, and in the River Liffey. Also in the stream flowing from Lough 
Eio-hter, on ( -arrantuohill Mountain, in Co. Kerry. Arrlienurus insulanus, 
Koenike : a single immature specimen of this species occurred in a small Chara 
pool at Gollierstown, Co. Dublin, in October. The male has not been described. 
The female is red in colour, and is remarkable on account of the large wing- 
shaped genital plates and the long and narrow epimera especially of the third 
and fourth pairs. The species is well figured by Dr. Koenike (26) ; the type 
was found on Norderney. 1 believe this species has also been found by 
Mr. C. D. Soar in England. 
Apart from a few records of the common Hydryphaiites ruber, de Geer, 
nothing has been published on the species of Hydryphantes occurring in 
Ireland. I have recently been making a preliminary examination of 
specimens of this interesting genus from various Irish localities, and find there 
are at least six species found in this country, counting //. prolongatus, Thon, 
of specific rank. A certain amount of variation occurs in the form of the 
eye-plates of Hydnjpluintes ; and as the structure of the plates is of great use 
in the identification of the species, a series of figures are given in the present 
paper, in the liope that they may be of interest for comparison with those of 
the same species in other countries. 
