THE SOhPUGIDJi OF AMEKICA PUTXAM. 251 



form. Tlie abdoineu is composed of ten segments with the o'enital 

 openings on the under side of the first, and the anus forming a ver- 

 tical slit on the tentii. There are two spiracles between the first 

 and second thoracic segments, just behind the coxte of the second 

 feet, and two each on the second, tiiird, and sometimes also on the 

 fourth abdominal segments. The body and limbs are clotlied with 

 hairs and spines in great variety, and varying in character among 

 the dift'erent genera and species. The particular structurt- of the 

 vari<ms parts, li;)th external and internal, and the functions which 

 they perform is a subject of gr.'at interest, but of which 1 do not 

 at present feel prepared to speak. 



Until 1842 these animals were regarded as forming the single 

 genus (j ((/((x/es or So/jiui/u. In this year C. !>.. Koch divided the 

 group into five genera based upon the number of joints of the tarsus. 

 This divisi(m proved so unsatisfactory that it was not adopted by 

 later authors, as for instance Gervais, and Dufoui-, who have each 

 treated of the group as consisting of a single genus. In 1879 M. 

 Eugene Simon published a new classification in which he has detiiu^d 

 ten genera. To these Dr. Karsch has recently added five, making a 

 total of Hfti'en genera. Of these five are American, namely: Dat- 

 aw.^^ Simon, (= (jhnu't/ Koch), Clinhis Simon, Afuvunucia '^imon., 

 Zerhina Karsch. l)<i(si(( Karscli. 



In iJdtamis the anterior margin of the cephalic shield is nearly 

 straight, and the fingers of the falces are unlike in the two sexes ; 

 the females iiaving both the fixed and movable fitigers curved and 

 armed with t(!eth, while the males have the upper finger nearly 

 straight and unarimHl. />. imllipe.-^ (Say) was first colh^cted in 1820 

 by Thomas Say, near the base of the Rocky Mountains in Colorado, 

 and may at present be regarded as our most common species, being- 

 found also in Kansas, Nevada, and Wyoming. It is aI)out twenty- 

 four mm. long (including jaws), of a pale fawn color, with an inter- 

 rupted indefinite dark (hjrsal band, and tht^ metatarsus of the max- 

 illary palpus furnished simply witli fine slender hairs, some of tiiem 

 very long, (i . sulnilata Say, is l)ut the male ui pallipfH. This 

 species is known to hide under stones and "buffalo chips" in perfect 

 solitude during the day. They an" very pugnacious and have been 

 reported by Dr. Gehrung to occur in houses in Denver, and to prey 

 upon the bed-bug. I), siilfuria Simon, is about the size of pallipcH^ 

 of a grayish color with a dark dorsal band, and has the metatarsus 

 of the maxillary palpus furnished with numerous short conical spines. 

 It has been collected in Texas by Mr. Belfrage, and in Colorado by 



