558 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxviii. 



23. Fifth legs visible dorsally; males or females; genital segment subquadrate. 



abbrevialus (Kroyer, 1863). 



23. Fifth legs invisible dorsally, all females 24. 



24. Genital segment rectangular, much longer than wide, no lobes; sides nearly par- 

 allel bremcaudatus (A. Scott, 1901 ) . 



24. Genital segment rectangular, much wider than long, no lobes; sides nearly par- 

 allel parvus (B-Smith, 1898, a) . 



24. Genital segment obovate, as wide as long, sides strongly curved; small plates on 



free segment centrodonti (Baird, 1850 ) , p. 652. 



24. Genital segment obovate, deeply lobed; lobes acute, conical; free segment nar- 

 row and long balistse (Steenstrup and Liitken, 1861 ), p. 601. 



25. Abdomen three-jointed; genital segment flask-shaped, truncate posteriorly. 



anyustatus (Kroyer, 1863). 



25. Abdomen two-jointed, of varying lengths 26. 



25. Abdomen one-jointed, of varying lengths 34. 



26. Abdomen longer than the genital segment, males or females 27. 



26. Abdomen about the same length as the genital segment 28. 



26. Abdomen half as long as the genital segment or more , _ 31. 



27. Males, genital segment quadrangular; free segment as wide as long. 



hirsutus (B-Smith, 1898, a). 

 27. Males, genital segment narrow spindle-shaped; free segment four times as 



wide as long bonito, new species, p. 589. 



27. Females, genital segment acorn-shaped; free segment twice and a half as 



wide as long didifer, new species, p. 582. 



28. Males, fifth legs visible dorsally; genital segment acorn-shaped; first abdomen 



joint smaller robustus (B-Smith, 1898, b). 



28. Males, fifth legs invisible dorsally - 29. 



28. Females, fifth legs plainly visible 30. 



28. Females, fifth legs invisible dorsally; genital segment oblong; basal abdomen 



joint the longer cybii (B-Smith, 1898, a). 



29. Genital segment barrel -shaped, only a little longer than wide, corners angu- 

 lar thijmni (Dana, 1852), p. 603. 



29. Genital segment narrow, club-shaped, twice as long as wide, corners rounded. 



trichiuri (Kroyer, 1863). 

 30. Genital segment obcordate; basal abdomen joint four times the terminal. 



robustus (B-Smith, 1898, b). 

 30. Genital segment oblong, widest posteriorly; terminal abdomen joint much the 



longer thymni (Dana, 1852), p. 603. 



31. Males, fifth legs not visible dorsally - 32. 



31. Females, fifth legs not visible dorsally 33. 



32. Genital segment orbicular, half as wide as carapace; basal abdomen joint short 



and wide infestans (Heller, 1865). 



32. Genital segment elliptical, one-third as wide as carapace; basal abdomen joint 



quadrangular Jtsemulonis ( Kroyer, 1863) , p. 606. 



33. Genital segment oblong, narrowed anteriorly ; deeply emarginate posteriorly ; 



lobes long infestans (Heller, 1865). 



33. Genital segment flask-shaped; slightly emarginate posteriorly; lobes short 



and broad belones ( Kroyer, 1863 ) , p. 586. 



33. Genital segment orbicular, as long as wide, evenly rounded; basal abdomen 



joint longer vexator (Heller, 1865). 



34. Abdomen obconical, longer than the genital segment; the latter flask-shaped; 



males ph ipsoni (-B-Smith, 1898, a ) . 



34. Abdomen same length as genital segment; the latter oblong; fourth legs short 

 and weak; females dublus (T. Scott, 1894). 



