Spiders and Their Near Relatives 



The first segment of the chelicera bears on its under side an 

 appendage, which is termed the jlagellum. In its most highly 

 developed form, as seen in Chthonius (Fig. 44), the flagellum 

 consists of a slender transparent stalk divided at its extremity 

 into a greater or less number of branches, which may be simple 

 or divided into secondary branches, and which are always clothed 

 with fine hairs. In the simpler form as seen in Chelifer it consists 

 of a row of three or four filiform appendages (Fig. 43/). The 

 flagellum is extremely delicate and therefore difficult to study. 



The chelicerae function as spinning organs, and as such are 

 discussed later. 



The pedipalps are enormously de- 

 veloped and chelate, resembling those 

 of scorpions. The chelae are furnished 

 with scattered tactile hairs, which must 

 serve as feelers. "The comparatively 

 slow, deliberate manner of hunting prey 

 may account for the fact that they re- 

 quire no more specialized feelers than 

 the pedipalps themselves, which are, as 

 every one who watches them alive knows, 

 highly sensitive" (Bernard '96). The coxae 

 of the pedipalps are extended forward 

 so as to form masticatory plates or they 

 bear distinct endites; these serve to hold 

 the prey in front of the mouth, and per- 

 haps also function as jaws. 



All of the four pairs of legs are 

 fitted for walking (Fig. 41). The seg- 

 mentation of the legs in this order is 

 somewhat different from the usual type in the Arachnida. The 

 tibia is not divided, in other words a patella is wanting. On 

 the other hand, with many pseudoscorpions, the femur consists 

 of two, more or less distinct, segments; when this division 

 exists, the proximal segment may be termed the second tro- 

 chanter. This second trochanter is sometimes a very distinct 

 segment (Fig. 4s a); but in other cases it is a triangular seg- 

 ment, closely joined to the femur (Fig. 45 b), and resembling 

 the trochanter of many beetles. 



This segment which I have designated the second trochanter 



Fig. 44- 

 CHELICERA OF CHTHONIUS 



s, spinneret /, flagellum 



41 



