642 PROCEEDINGS O/' THE NATIONAL MUSEUM. 



oil-immersiou lens. H. E. Ewing (17) and the present writer have 

 already pointed out that a careful examination of red spider species 

 with up-to-date equipment has revealed the fact that the tarsal and 

 palpal structures are not nearly as simple as Banks (9) and other 

 earlier v/orkers have indicated. Also for years it was believed that 

 each of the numerous host plants supported a distinct species, and 

 that each of the many color forms represented a species. In this 

 mannei- a very annoying confusion regarding synonymy arose, which 

 has not been entirely straightened out at the present wTiting. 



A sort of controversy has arisen between certain of the recent work- 

 ers concerning the correct nomenclature of the microscopic struc- 

 tural parts of the tip of the tarsus. Tragardh (18) claims that 

 Zacher and Ewing each had the wrong conception of what con- 

 stitutes the em}>odium. The former asserts that the bases of the 

 tenent hairs are homologous* with the claws of other mites. lie 

 claims that what Banks, Pawing, and others have been calling the true 

 claw is but the empodium which in the several s})ecies is variously 

 modified so as to exhibit from one to six claw divisions. 



It was Zacher (13) who first recognized the importance of the penis 

 as possessing specific variations, and Ewing (15) followed soon after 

 with an amplification of the penis characters. Tragardh (18) also 

 recognizes the taxonomic value of the variation shown by the penis 

 of the various species. The present writer's studies have similarly 

 tended to corroborate the opinions of the above workers as to the 

 value of the penis in possessing specific characters. Dr. W. Dwight 

 Pierce has pointed out to the writer the resemblance of this chitinous 

 organ to the oedeagus of insects, especially the Strepsiptera. He 

 believes that the penis will be found to be a delicate extrusible tube 

 within this chitinous oedeagus. Perhaps detailed study will bear him 

 out. The wT-iter has not had this opportunity as the suggestion was 

 made while Doctor Pierce was reading over the completed manuscript. 



The "thumb " or terminal joint of the palpus has long been accorded 

 a place of importance among the taxonomic structures. The char- 

 acters of this member, however, appear through recent studies to be 

 rather too constant to furnish specific features of a very satisfactory 

 nature. There are almost without exception seven appendages, 

 including, two "fingers," two digituli, and three short hairs. About 

 the only characteristics of these appendages that appear useful are 

 the outlines of the terminal and the dorsal "fingers" and their pro- 

 portionate sizes one to the other. 



The dorsal body bristles or appendages also offer some assistance 

 in the taxonomy, although, aside from the two members of the genus 

 Anychus, the number and arrangement of these hairs seem to be 

 nearly constant. 



