1910] The Palpi of Male Spiders 173 



In most cases the conductor can be recognized at a glance by 

 its peculiar texture; sometimes it is chitinized to a considerable 

 extent, but even then it usually has a membranous margin; 

 and in any case it can be recognized by its relation to the tip 

 of the embolus in the unexpanded bulb. 



The embolic subdivision. — Closely connected with the mem- 

 branous base of the conductor is the base of a separate subdi- 

 vision of the apical division of the bulb; as this portion bears 

 the embolus it may be termed the embolic subdivision. 



The radix and the stipes. — Immediately following the mem- 

 branous neck that connects the middle and the apical divisions 

 of the bulb and parallel with the membranous base of the con- 

 ductor, there are two segments of the embolic subdivision; to 

 the basal one of these I apply the term radix (Fig. 10, ra.) ; and 

 to the second, the term stipes (Fig. 10, st.). For a more dis- 

 tinctly segmented condition of the base of the embolic sub- 

 division see the figures of Aranea circulata given later (Fig. 18 

 and 19), where the corresponding parts bear the same letters. 



The embolus. — The organ through which the ejaculatory 

 duct opens, the embolus, is comparatively simple in Linyphia, 

 being a short spinelike part (Fig. 10, emb.). 



The lateral subterminal apophysis. — In Linyphia phrygiana 

 there is developed a remarkable platelike apophysis, which 

 serves to protect the exposed face of the unexpanded bulb. 

 In Figure 10 (/. st. a.), only the edge of this apophysis is shown; 

 but in Figure 11, the broader face of it is represented. I desig- 

 nate this the lateral subterminal apophysis as it occurs on the 

 lateral aspect of the unexpanded bulb, and also to distinguish 

 it from an apophysis developed on the opposite face of the bulb 

 in a subterminal position, which occurs in certain other genera. 



The terminal apophysis. — The embolic subdivision ends in 

 a strongly chitinized lobe, which may be designated the terminal 

 apophysis (Fig. 10, /. a.). To apophyses of this kind Menge 

 applied the term retinacula; but as this term predicates their 

 function, which in some cases is obviously not that implied by 

 the name, I prefer apophysis with a modifying term indicating 

 the position of the particular apophysis described. 



The Aranea Type of Palpus. — I have selected the palpus 

 of Aranea frondosa {Epeira stri.x) as an example of an extremely 

 speciaHzed palpus. In Figure 12 the entire palpus, with the 

 bulb unexpanded, is represented slightly twisted so as to show 



