Pl'.DAI. XOSIi: !.\ TK \|--l)(i()R SI'IKKKs. 337 



the central piirtion of the hair c)j)ens i'reciv \<> the exterior. 

 Now, thoiij^h ii is (hlfii'iilt to see how tlie inii)act of olfactory 

 particles on die solid chiiiiious tii)s of an ordinary hair can he 

 sufficient for an olfactor\ sensation. 3et it seems (|nite possihle 

 that such i)articlcs on a sco])nlar hair nia\- he hroug-ht into direct 

 contact with livinof material or with liquid exudate from livinsj 

 cells, in which case chemical chani^^es may restilt in the settin«^ 

 up of afferent olfactory imi)ulses. I-'urther investij^^ations i>n 

 the minute structure of sco])ular hairs and their relationship 

 with the subjacent cells and the nervous system will he re(|uirod 

 liefore this explanation can he established. 



it may be noted that the scoi)ula is (jttite absent in females, 

 which, as we have seen, are dexoid of an olfactory sense; yet, 

 on the other hand, it is well established that an olfactory sense 

 is present in njany spiders which have no trace of a scopula. 

 riie tarsi of the female are relatively much shorter than tho>e 

 of males; moreover, the tarsus of the hrst leg of the male is 

 tlistinctly swollen and more strons^l}- sco])ulate than th;it of the 

 fourth leg. which i.s not swollen. 



The alternative ixjssibilitx' which would connect the olfac- 

 torv sense with Ivriform or<^ans or related structtires does not 

 seem ade(|uatelv sti])])orted ])\ the facts of distrihtition ot such 

 oru;ans. These org-ans are I'.resent on each joint of the legs, 

 except the tarsi, in both male and female, being ajjparently 

 equallv well develoi)ed in the tw(» sexes. The organs at 

 the a])ex of the femur are larger and more complex than those 

 at the apex of the metatarsus, yet L could trace no sensitiveness 

 to olfactory stimuli in the neighbourhood <^f the femora. How- 

 ever, in addition to the typical lyriform organs, there are to be 

 found on the legs of Stasitnopus a great number oi minute pores. 

 These ])ores seem to be smaller than the simi^le slits distinguished 

 bv Dr. MTndoo in the various s])ecies he examined. Thev are 

 perha])S comparable with the olfactory pores of insects as 

 described ancl figured by that author in the honey bee and other 

 hymenojitera. I have found such j)ores also in Mo(/fjridffca 

 cocf/ciisis l^ircell and in Hcnnacha hicolor Pocock, bttt in the 

 latter case they are very easily confused with the exposed 

 sockets of broken hairs. In Stasiuiopus. hcnvever. the i)ores can- 

 not possibly be confused with hair sockets, for the\- are con- 

 siderably smaller than the ])its of neighbottring hairs. They 

 occur abundantly, for exam])le, in the midst of the sjjinous areas 

 of the tibia and metatarsus of a female leg, where fine hairs do 

 not occur. The distribution of these j^ores is very general, and 

 they are as abundant in females as in males. They occur on all 

 the joints of the legs and are not speciallv accumtilated on the 

 tarsi and metatarsi. Indeed, the total number of pores on 

 either of these segments is distinctlv less than that found on the 

 femur. 



It is interesting to speculate on the inirpose of thi> olfac- 

 tory sense which presumablv does not originate in the feet of a 

 male until the final moult which ushers in the adult stage. The 



