54 The Irish Naturalist. February, 



APTERA. 



BY PROF. GEO. H. CARPENTER, B.SC. 



A number of Springtails and Bristle-tails were gathered by 

 J. N. Halbert during his several visits to Lambay, and from 

 these it has been possible to compile the following list, which 

 includes eleven species of the former and three of the latter 

 group. All the Collembola are common Irish species, except 

 Xenylla humicola, which is a shore-haunting Springtail, northern 

 in its range and new to the Irish fauna. The complete absence 

 of Sminthuridae and of several large genera like Achorutes is 

 remarkable. The great interest of the collection, rests however 

 in the Thysanura (Bristle-tails). The examination of the 

 Machilida^ has shown that some of the Lambay specimens, 

 together with a number of Irish specimens from various locali- 

 ties, which I had erroneously regarded as Machilis poly pod a 

 (Linn.) belong to the genus Prsemacbilis which Silvestri has 

 recently 1 proposed for a number of Italian and exotic species. 

 The result is thus a remarkable and unexpected addition to the 

 southern section of the Britannic fauna. Prsemachilis may be 

 readily distinguished from Machilis by the presence of only one 

 pair of exsertile vesicles in association with the abdominal 

 appendages. In Machilis there are two pairs of these vesicles 

 from the second to the fifth abdominal segments inclusive. The 

 central sternal sclerite of an abdominal segment in Prasmachilis 

 is regularly triangular in form (see Plate 16, fig. 9). 



COLLEMBOLA. 

 ENTOIMOBRYIDJE. 



Entomobrya muscorum (Nic.) Tullb. — Freshwater Bay, one 



specimen, October, 1906. 

 E. alboclncta (Tempi.) — N.W. coast, three specimens, October, 1906. 

 Orchesella cincta (De Geer). — N.W. coast, two specimens, October, 



1906. One in June, 1906. 

 Tomocerus plumbeus (Linn.) [longicornis, Mull). — Freshwater Bay 



and N.W. coast, common, October, 1906. 

 T. trldentlferus (Tullb.)--Same localities as preceding, but apparently 



less common. 

 Lepldocyrtus cyaneus, Tullb.— Freshwater Bay, October, 1906. 

 Isotoma vlrldis (Bourl.)— N.W. coast, October, 1906. 

 Anurophorus larlcls (Nic.)— Common in moss. 



1 Kedia, ii., 1904, p. 2. 



