Carpkntke — The Apterygota of the Seijchellcs. 9 



known Machilidae. So conspicuous are these distinctive features that the 

 establishment of a distinct genus for the species might be thought desirable 

 by some entomologists. But in the structure of its jaws, feet, and abdominal 

 segments and appendages the insect resembles so closely the two Corethro- 

 machilis already described, that it seems reasonable to consider it cogeneric 

 with them. It is suggestive that in C. gilha the tendency to develop conical 

 out-growths should be displayed both on the head and the metathorax. 



In the feeler the basal segment is three times as long as broad, and the 

 regions of the flagellum have about 18-20 segments each (fig. 48). The 

 arrangement of the ocelli is most remarkable, the median one looking directly 

 downwards and those of the pair being placed close together on either side of 

 the conspicuous prominence in front of the eyes (figs. 46, 47). The eyes are 

 in contact for a comparatively short distance along the median axis of the 

 head. As in 6'. Gardineri, the 7nandible (6g. 49), toiigice {&g. 60 hy], m.a,xillu\a. 

 (fig. 53 Micl), maxillarij galea (fig. 51^), and lahium (fig. 52) are exceedingly 

 broad in proportion to their length. The maxillary lacinia has a head with 

 complex brush, resembling that of C. Gardineri (figs. 7, 8, 9) so closely that it 

 is needless to figure the details. The legs (figs. 54, 55) also are very like those 

 of C. Gardineri; the scopula, however, in C. gibba is rather smaller, and the 

 claws are a little longer than in the former. I'he abdomen of C. gibba is 

 relatively small as compared with that of the other species, as may be seen 

 by comparing the outlines of the abdominal segments (figs. 56-60) with those 

 of the corresponding structures on Plate II. On the second segment (fig. 56) 

 the stylet has a short but distinct spine. The ninth stylet (fig. 60 st) has a 

 slender, acute spine almost its own length. The male gonapophyaes of C. gibba 

 are weakly developed and feebly jointed (tigs. 61-62). 



It is well known that various interpretations of the genital armature of 

 insects have been given by different students. The term gonapophgses 

 emphasizes the correspondence of these structures in the Thysanura with 

 those in the (Jrthoptera and other insects which have a typically developed 

 male and female armature. Terms such as " telepodite " and " parameron " 

 have been applied by some authors who, like Escherich ('04, pp. 2o-6), regard 

 a genital process as comparable to the terminal portion of a thoracic leg. 

 Silvestri ('05, pp. 794-7) has argued convincingly in favour of the opposite 

 view : that the abdominal stylets, rather than the gonapophyses, are to ub 

 regarded as appendicular ; and he has brought forward some reasons for con- 

 sidering the latier as homologous with the exsertile vesicles on the unmodifieu 

 abdominal segments. It is at least suggestive that the genital segments of 

 the abdomen never bear exsertile vesicles in the Thysanura. 



11. 1. A. FROC, VOL. XSXIII., SECT. E. [C] 



