134 BULLETIN 168, UNITED STATES NATIONAL MUSEUM 



Proisotoma (Proisotoma) longispina: 



190. Dorsal aspect of bead, X 109. 



191. Eyes, postantennal organ, and base of antenna of right side, X 400. 



Plate 19 



Proisotoma (Proisotoma) longispina: 



192. Right midfoot, X 673. 



193. Left mucro and end of dens, X 613. 



194. Dorsal aspect of left mucro, X 1,060. 



195. Right mucro, X 1,060. 



196. Dorsal aspect of right mucro, X 1,060. 



197. Dorsal setae of second abdominal segment, X 507. 

 Proisotoma (Proisotoma) viinuta: 



198. Eyes and postantennal organ of left side, X 653. 



199. Sense organ and third antennal segment of left side, X 1,640. 



200. Left hind foot, X 1,728. 



201. Left hind foot, X 1,100. 



202. Left aspect of furcula, X 527. 



203. Right mucro, X 1,728. 



204. Left mucro, X 980. 



205. Left mucro, X 1,120. 



206. Left mucro, X 980. 



207. Left aspect of tenaculum, X 960. 



Plate 20 



Proisotoma (Proisotoma) sepulcralis: 



208. Eyes and postantennal organ of left side, X 757, 



209. Sense organ of third antennal segment of left side, X 757. 



210. Right hind foot, X 630. 



211. Right mucro, typical, X 1,012. 



212. Mucro, common variation, X 1,012. 



213. Right mucro, rare variation, X 870. 



214. Right mucro, very rare variation, X 731. 



215. Left aspect of tenaculum, X 735. 

 Proisotoma (Proisotoma) frisoni: 



216. Postantennal organ and base of antenna of right side, X 757. 



217. Right postantennal organ, X 952. 



218. Sense organ of third antennal segment of left side, X 1,896. 



219. Right hind foot, X 952. 



Plate 21 



Proisotoma (Proisotoma) frisoni: 



220. Left aspect of furcula, X 640. 



221. Left mucro, X 1,053. 



222. Right mucro, from same specimen as figure 221, X 1,053. 

 Proisotoma (Proisotoma) brevipenna: 



223. Left fore foot, X 960. 



224. Left mucro and end of dens, X 960. 



225. Dorsal setae of metathorax, X 411. 



