i9ii> Carpentkr. — New Irish Apterygota. 85 



The present insect is abundantly distinct from P. 

 ScJwtti, and from all the longer -known species of the group. 

 Its nearest European ally is P. borealis (Axelson, '05, p. 

 791), a Finnish species with a comparatively short and 

 thick body, a narrowly elliptic post-antennal organ, the 

 fourth abdominal segment half aaiiong again as the third, 

 and a very well -developed catch. In P. borealis, however, 

 the ocelli are all of equal size, the empodial appendix has 

 no bristle-like ending, and the mucro is short and stout. 

 Axelson calls attention to the likeness which his P. borealis 

 bears to a tropical species from a very distant part of the 

 world. — P. inaequalis (Schaeffer, '99, p. 403, figs. 4, 5), found 

 in the islands of the Bismarck Archipelago. Curiously our 

 Irish insect is still closer to P. inaequalis, whose spring, as 

 figured by Schaeffer, might almost have been drawn from 

 the Ballyclare springtail ; the mucro in the latter is, 

 however, relatively longer, though of closely similar shape. 

 P. inaequalis is a very small springtail, only 75 mm. long. 

 Its ocelli are all of equal size, and the disproportion in the 

 relative lengths of the fourth and third abdominal segments, 

 (as 5:3) which gives the species its name, is greater than 

 in P. ultonica (as 3:2). 



This discovery of another Irish species of Proisotoma, 

 showing such noteworthy and unexpected affinities with 

 both arctic and tropical springtails is of quite exceptional 

 interest. It supports strongly the view that our apterous 

 fauna is of a relatively high antiquity, and presages still 

 more remarkable results when that fauna shall be more 

 thoroughly known. 



Royal College of Science, Dublin. 



References. 



'05. W. M. Axelson. — Einige neue Collembolen aus Finland. Zoolog. 

 Anz., xxviii., 1905, pp. 788-794. 



'03. C. BoRNER. — Neue altweltliche Collembolen, nebst Bemerkungen 

 ' 2ur Systematik dcr Isotimen und Entomobryinen. Sitzb. der GeseUsch. 

 naturforscheud. Freunde- Berlin, 1903, pp. 129-182. 



'04. L. EscHERicH • — Das System der Lepismatiden, Stuttgart, 1904. 



'99. C. Schaeffer. — Die Collembola des Bismarck-Archipels. Archiv. 

 f. Naturgeschichte, 1898, pp. 393-426, pi. xi., xii. 



' 10. F. V. Theobald. — Report on Economic Zoology for the year ending 

 September, 1910. 5. E. Agricultural College, Wye. 



