134 External Sexual Characters in Ricimdei 



9. External Sexual Characters. Stages of Development. 



Of Gryptostemma Karschii we have had adult specimens of both sexes before us ; of 

 C. Sjostedtii and C. Westermannii we have had an adult male and a younger female ; of the 

 genus Cryptocellus we have had only one specimen of each of the two species, but fortunately 

 the male of the one species and the female of the second. Our material for a direct comparison 

 of the sexes has therefore not been large, but it has sufficed for us to ascertain that secondary 

 differences according to sex exist as to the equipment of the legs with processes, and in similar 

 features of lesser weight. These secondary sexual characters vary in the different species which 

 we have examined, and we shall therefore treat of them in our descriptions of the species. 



But besides these there is a sexual difference in the structure of the metatarsus and the 

 tarsus of the third pair of legs, which appears to be constant in the main, though differences 

 may be noted in the smallest details. Very little has been said on this subject by Karsch 

 (c, p. 32), and we therefore consider it proper to give as exhaustive an account of this remark- 

 able arrangement as it certainly deserves. 



The metatarsus of the third pair of legs in the male of Gryptostemma (PI. VIII., figs. 3 a 

 and 3 h, h) has the appearance of being much thickened, which, however, in reality is mostly 

 due to the dorsal margins being laised in the shape of keels. Towards the middle of the 

 joint these keels approach one another somewhat, and they are here connected by means of a 

 transverse ridge, of which the distal face is concave. In this manner the doi'sal face of the 

 joint is divided into two hollow lodges, of which the distal one is wider and deeper than the 

 proximal one. In Gryptocellus the metatarsus is much thicker, and as it were inflated (PI. IX., 

 figs. 3 a and 3 i), and the cavity on the dorsal face is wide and deep, but shorter than in 

 Gryptostemma, nor is it divided into two lodges. In both genera a process is found (PI. VIIL, 

 fig. 3 /i, c; PI. IX., figs. 1 /(, c and 3 i, c), near the proximal extremity of the dorsal surface of 

 the metatarsus, connected with it by means of an articulation which renders it movable. In 

 Gryptostemma (PL IX., fig. 1 h) the process is easily seen to be placed close to the anterior 

 side of the joint and to lie in a special excavation on the joint from which only the point 

 protrudes, whilst in Gryptocellus (PI. IX., fig. 3 i) its place is just a little in front of the 

 middle line of the joint, nor is the process here placed in a special excavation. The process 

 presents a double curvature, is compressed and fairly evenly pointed ; much the largest — 

 proximal — half of it is closely covered with fine hair, and in Gryptostemma at the same time 

 granulated. The curved point turns backwards. 



The tarsus of the third pair of legs in the male is distinguished by a very remarkable 

 conformation of the two first joints, particularly of the first. The posterior dorsal margin of 

 the second joint is raised into a high almost perpendicular plate (PL IX., figs. 1 h, 3 /(, and 

 3 i, e° and e'), which is scooped out like a spoon (our 'lamina cyathiformis '), and which varies 

 not a little in shape. Sometimes it is formed only by the posterior margin of the joint, and 

 in this case (PL IX., fig. 3 i) the excavation turns forward : in other cases the plate extends 

 besides over the distal end of the joint, and the excavation turns towards the base and the 

 anterior side of the joint (PL VIII., fig. 3 It ; PL IX., fig. 1 h). In any case this excavation 

 serves to receive the distal extremity of the movable process on the first tarsal joint, which 

 we shall mention presently, and the shape of the excavation corresponds to the shape of the 

 process. The posterior dorsal margin of the first tarsal joint is similarly raised into a plate, 

 which, however, is lower (PL IX., fig. 3 A), or at its distal extremity carries a compressed conic 



