1 s2 



[midls lintowoloii^idil Socu'ty of Anicricd \\\)\. Ill 



Tiiii Anklli (>i- nil-: SL'HTKi;rLrM. In Anuica, the cliiii- 

 nized part of the wall of the basal division of the bulb, the sub- 

 tej^nilum. is reduced to a ringlike sclerite (Fig. 24, i.); Init in 

 certain other genera, the subtegulum is cup-shaped or basket- 

 like, in Aiiclcfiii uccvia (Fig. 24, 2), one side of the subtegulum 

 is greatly thickened; at the i)roxiinal end of this thickening, 

 which corresponds to the lunate ])late, there is a condyle, which 

 articulates with the i)etiole; and at the distal end, there is a 

 condyle, which articulates with the tegulum. The other side 

 of the cuplike subtegulum contains in its wall several parallel, 

 incompletely ringlike sclerites; these may be termed the anclli 

 of the subtegulum. In Dolomcdcs fontauus (Fig. 24, 3), the 

 anelli of the subtegulum are greatly thickened and form prom- 

 inent projecting ridges. 



It is probai)le that the presence of the anelli of the sul)te- 

 gulum. and their nature when present will afford characters of 

 use for taxonomic ]niri)oses. 



Fi... 21. rii; 



kinds r.f suhtcsjiilum. 



TiiK DiFFKRENT TvPEs OF Emholus. — The form of the 

 embolus varies greatly in difTercnt species of spiders. Two prin- 

 cipal ty])es can be recognized, the connate and the free; and the 

 free type includes three subtypes. 



The connate type of embolus. — In the connate type, the 

 embolus is not separate from the middle division of the bulb 

 but is merely a more slender continuation of it. as in the taran- 

 tulas, Loxosceles (Fig. 4). and Aricuhia. 



The free type of embolus. — In the free type of embolus, there 

 are one or more movable articulations between the embolus ami 

 the middle division of the bulb. In the free type, the embolus 

 varies greatly in form; but the ditYerent forms can be grouped 

 under three heads: coniform, lamelliform. and spiral. 



.4 coniform embolus. — In this type, there may be a broadly 

 expanded base; but the ])rojecting ])art of the embolus is, a 

 straight or slightly curved cone. The embolus of Aranea 

 fro)i(lns(i (Fig. 25. /) is an example of this type. 



