Pedipalpi from the Lower Amazons. 333 



Measurements in millimetres. — ? . Total length 77 ; length 

 of carapace 8, of tail 46, width of its iirst and fourth seg- 

 ments 5, length of fourth 8 ; width of vesicle 3, of brachium 

 3*3, of hand 4 ; length of brachium 9, of hand-back 5*1, of 

 movable digit 10"8. 



S. Total length 97; length of carapace 9"5, of tail 61, 

 width of first segment 5, length 7*7, width of fourth 6*3, 

 length 1 1 ; width of vesicle 3'8, of brachium 3'6, of hand 5*8 ; 

 length of brachium ITS, of hand-back 8, of movable digit 13. 



Loc. of type {S)- Above Iquitos, on the Maraiion or 

 Amazons. 



The ]\Iuseum has two males and three females of this form 

 from the above locality, and ^Ir. Cambridge procured one 

 male specimen at Parintins, up the river above Santarem. 

 This example has the clieUe rather more slender than in tlie 

 two males trom Iquitos ; but since tliese two are not quite 

 alike in thestructuie of the a|)pen(lage, it would be incautious 

 to attach a new name to the Parintins specimen without 

 further material wherewith to test the constancy of the differ 

 ences. The distinctions between this form and forcipida 

 will be further discussed in a future paper. 



Tityus silvestrisj sp. n. (Fig. 3, p. 362.) 



Belonging to the columbtanus group of species and approach- 

 ing most closely to the Demerara form T. Quelchii, Poc. 

 (Ann. & .Mag. Nat. Hist. (6) xii. p. 314. pi. xlv. rig. 1, 189 V), 

 and to the Paraguayan form T. pitraguaijensis, Krae|)elin 

 (Jahrb. Hamburg. Anstalten, xii. p. 19, 18!>5), of which the 

 British Museum has examples collected at Assuucioii by 

 Dr. Bohls. 



The dorsal and sternal surfaces of the trunk densely s[)otted 

 black and yellow ; there is, however, a conspicuous bright 

 yellow T-shaped mark on the fore part of the carapace, a 

 similar mark being much less conspicuous in parayuaijensis 

 and not noticeable in Quelchii^ which is of a much more 

 uniform tint and less distinctly mottled. 



In silvestris, moreover, not only are the maxillary lobes 

 infuscate throughout their length, but the dark pigment, in 

 addition, spreads on to the coxte of the second, third, and 

 sometimes also of the fourth leg, whereas in the specimens ot 

 the other two species that I have seen the maxillary lobes are 

 intuscate oidy at the tip, there being, however, in p'lrajuai/- 

 eiisis also a single spot upon the coxte of the second leg. 



Jn structural features Quelchii has better developed granu- 

 lation and stronger keels, the sculptnring of p(ir'((/tia/je/i!iis 



