40 Scientific Proceedings, Royal Dublin Society. 
Family ENTOMOBRYID/E. 
Genus Isoroma, Bourlet. 
Isotoma hibernica, sp. nov. (Plate II., fig. 1-7.) 
Length, 3 mm. Feelers, twice as long as the head. Post- 
antennal organ, oblong-oval; eight ocelli on each side of head 
(fig. 2). Feet without tenent hairs; large claw with two teeth, 
small claw with one (fig. 6). ‘Trunk segments with very elongate 
serrate bristles (fig. 5), especially prominent on the third, fourth, 
fifth, and sixth abdominal segments. Spring more than half as 
long as the body, with very elongate dentes (thrice as long as the 
manubrium); mucro with an apical tooth, and two dorsal teeth 
close together (fig. 7). 
In colour J. hibernica is dark violet-brown, with ochreous 
mottlings on the head and trunk-segments (fig. 1); the feelers 
and legs are blue-violet, and the spring yellowish-white. The 
mandible (fig. 4) is of the form usual in the genus and family. 
This species is closely allied to J. viridis, which it resembles 
closely in the structure of the feet and the mucrones. It is, how- 
ever, smaller, and has the feelers, the spring, and the serrate 
bristles on the hinder abdominal segments relatively longer. The 
spring in this species, when pointing forwards beneath the body, 
reaches to the bases of the intermediate legs, recalling the 
excessively elongate spring of the Arctic genus Corynothrix of 
Tullberg. J. hibernica also differs from J. viridis in the arrange- 
ment of the ocelli, and in the proportional lengths of the antennal 
segments (as 8: 12:16:15). In J. viridis the second and third 
segments are equal in length, and the terminal segment relatively 
longer. The antennal organ (fig. 3) is represented by a low, 
broad tubercle. 
Genus EnromopryA, Rondani. 
Entomobrya anomala, sp. nov. (Plate II., figs. 8-15.) 
Length, 2°5 mm. Freelers thrice as long as the head, six- 
segmented (figs. 8,10). Six normal, and two very minute ocelli on 
