4 Proceedings of the Royal Irish Academy. 



B. Abdominal segments from 2nd to 7th, inclusive, with relatively 

 large triangular sterna. 



a. Only one pair of exsertile vesicles on any abdominal 



segment, ....... Pracmachilinae. 



h. Two pairs of exsertile vesicles on abdominal segments 



2-3, 2-4, 2-5, or 2-6, .... Machilinac. 



The last-named group (Machilinae) is alone represented in the collection 

 from the Seychelles. Three species, all new, differ so definitely from any 

 members of the family hitherto known that a new genus is required for 

 their reception. 



Corethromachilis' gen. nov. 



Feelers, maxillary palps, legs, and ninth abdominal stylets scaled. Apex 

 of mandible feebly tootlied. Lacinia of maxilla with a complex " brush " of 

 lanceolate bristles. Legs of second and third pairs with coxal processes ; 

 beneath the tip of the terminal (third) segment of the foot in all three pairs 

 a dense mass of lanceolate bristles forming a "brush" or scopula. Abdominal 

 segments with moderately large triangular sterna, the first, fourth, fifth, sixth, 

 and seventh with one pair of exsertile vesicles each, the second and third 

 with two pairs each. Male with feebly jointed gonapophyses on the eighth 

 and ninth abdominal segments; penis short, not reaching apex of the ninth 

 sub-coxa. Female with ovipositor not, or hardly, projecting beyond ninth 

 abdominal stylets. 



Type, CorcfhroiiiacliiUs Gardineri (sp. nov.) Seychelles. 



This genus is of interest from the reduction to two of those abdominal 

 segments which have two pairs of exsertile vesicles each. In the typical 

 genus Machilis there are four segments thus provided ; in Coryphophthalmus 

 (Verhoeff, '10) three. In this character, therefore, Corethromachilis ap- 

 proaches I'laemachilis and its allies, in which there is but one pair of 

 exsertile vesicles on each abdominal segment from the first to the seventh, 

 inclusive. But the most remarkable feature in Corethromachilis is found in 

 the wonderful arrays of bristles on the lacinia of the maxilla and beneath the 

 tip of each foot, forming the brush-like organs that have suggested the generic 

 name. Except in the case of the aberrant C. t/ibba, described below, there is 

 nothing to attract attention in the general appearance of the species. Indeed, 

 the naturalist studying the Machilidae is struck with a monotony throughout 

 the family in ihe main features of their superficial aspect, which is yet 

 accompanied by a range of variation in details of the exoskeleton which 

 afford reliable characters for classification. All the specimens of Coretluo- 



' Fiuui Koprt^pun, a broom, aud Machilis. 



