1880.] or THE GENUS ARGYRODES. 331 



synonyms of the foregoing species ; but although the present Spider 

 resembles A. inguinalis very nearly in colours, markings, and the 

 general character of the al)dominal form, it may be easily distin- 

 guished by the more obtuse and rounded form and black colour of 

 the apex. In A. inguinalis the apex is indeed obtuse and rounded ; 

 but its tapering form is continued throughout, and its upper part 

 and sides are completely silvery ; the central longitudinal band also 

 on the fore part of the upperside is paler, and tapers without in- 

 terruption to a fine point. There is considerable similarity, but still 

 a difference, in the form of the genital process in the two species. 



Fiom A. Jissifrons, Camb., $ , the present Spider may also be dis- 

 tinguished by the same characters as those which distinguish it 

 from A. inguinalis, Thor. 



Argyrodes amboinensis. (Plate XXIX. fig. 8.) 



Argijrodes amboinensis, Thor. Ann. Mus. Genov. xiii. p. 141 

 (1878). 



The length of the adult male is'2f lines to the spinners, and to the 

 apex of the abdomen 3| ; the length of the female, to the spinners 

 rather over 3 lines, and to the extremity of the abdomen 4 lines. 



This fine and beautiful species has been well described by Dr. T, 

 Thorell (/. c. supra). I have, however, thought it worth while to 

 include here one or two figures, and also a note upon the very dis- 

 tinctive characters of the caput. In the absence of figures it is 

 almost impossible to determine many of the Spiders of this group, 

 in which the peculiar structure of the caput assumes so many forms 

 differing from each other often in minute but important particulars. 



The fore part of the caput is divided into two lobes by a deep 

 and wide cleft; the superior lobe is the smallest, and has the four 

 central eyes on its upper side ; the inferior lobe projects considerably 

 beyond the superior one, its extremity is subconical, and about half- 

 way between the extremity and the base of the cleft there is, on the 

 upperside, a strong subangular point clothed with a tuft of black 

 hairs ; three strong sinuous bristles are directed forward from the 

 fore extremity on the upperside of the superior lobe ; there are, 

 besides these, numerous bristly hairs on and about both the lobes. 



As in most others of this group, the abdomen differs in form in 

 the two sexes. That of the male is longer in proportion, and has its 

 hinder extremity produced into a strong, somewhat cylindrical form, 

 rounded at its apex ; it is of a yellow-brown colour, ornamented 

 with brilliant silvery markings edged in some parts with deep blackish 

 brown, and disposed as in fig. 8. That of the female has these 

 silvery markings of greater extent and better defined than in the male, 

 and with many smaller silvery spots dispersed over the sides and 

 hinder part vide (fig. 8). 



The legs are exceeding long, slender, of a dull yellowish hue, 

 coloured rather lighter than the cephalothorax, and furnished with 

 fine hairs only. 



The palpi of the male are long, and similar to the legs in colour ; 

 the cubital joint is longer than the radial, curved and clavate ; the 



