ISOPODS OF NORTH AMERICA. 609 



Color dark brown, covered with numerous white .spots or Httle 

 stripes. Legs yellow, with the cox;e spotted with black. 

 Leno'th, 9 mm.; width, 4 mm.; height, 1.0 mm." 



108. Genus C YLISTICUS Schnitzler. & 



Body oblong, very convex, contractile into a ball. 



Head with lateral lobes distinct; median lobe small; front of head 

 marginate. Eyes distinct, lateral. Second pair of antennae long; fla- 

 gellum composed of two subequal articles. 



Lateral parts of the thoracic segments large. 



Abdomen not abruptly narrower than thorax; lateral parts of third, 

 fourth, and fifth segments well developed; terminal segment conically 

 produced. 



Opercular plates of all the pleopods furnished with trachea\ 



Inner branch of the uropoda inserted far in front of the outer branch, 

 near the inner antero-lateral angle of the peduncle. 



CYLISTICUS CONVEXUS (De Geer). 



Onisciis convexus De Geer, Mem. des Insectes, VII, 177S, p. 553, pi. xxxv, tio;. 11. 

 Porcellio spinifrons Brandt, Bull, de la 8oc. Imp. d. NaturaliHtes de Moscou, VI, 



1833, p. 15. 

 Porcellio Isevis Koch, Deutschlands Cnistaceen, 1835-1844, p. 6. 

 Porcellio armadilloides Lereboi:llet, Mem. de la Soc. du Museum d'Histoire Nat. 



de Strasbourg, IV, 1853, p. 65, pi. i, fig. 18; pi. in, figs. 88-94. 

 Cylistictis Ixvis ScHNiTZLER, De Oniscineis agri Bonnensis, 1853, p. 25. 

 Porcellio armadilloides Ki>iAnA^, Naf. Hist. Rev., IV, 1857, p. 279. 

 Porcellio convexns Johnson, Academisk Afhandling, Upsala, 1858, p. 32. 

 Porcellio armadilloides Bate and Westwood, Brit. Sessile-eyed Crust., II, 1868, 



p. 485. 

 Porcellio convexus Budde-Lund, Nat. Tidsskr. (3), VII, 1870-71, p. 240.— Stux- 



berg, Of vers, af Kgl. Vetenskaps Akad. Forh., 1875, p. 60.- 

 Cylisticus convexus Budde-Lund, Crust. Isop. Terrestria, 1885, pp. 77-79. (See 



Budde-Lund for further synonymy.) — G. O. Sars, Crust, of Norway, II, 



1899, p. 186, pis. XI, XII.— Richardson, Amer. Nat., XXXIV, 1900, p. 303; 



Proc. U. S. Nat. Mus., XXIII, 1901, pp. 565-566.— Stoller, 54th Report 



New York State Museum, 1902, p. 213.— Paulmier, Bull. New York State 



Museum, 1905, pp. 181-182. 



«The above description is adapted from the following one of Budde-Lund's: 



Oblonge ovalis, convexiuscula, iiitida, tenuiter et sparse punctata. 



Antennae exteriores . . . 



Linea marginalis frontalis recta; epistoma medio linea transversa. 



Cauda trunco abrupte angustior; epimera subdistantia. Annulus analis brevis, 

 subtriangulus, lateribus subrectis vel leviter incurvis, apice obtuso, supra sulcatus. 



Color ex nigro brunneus, maculis vel striolis numerosis albidis conspersus. Pedes 

 flavi, coxis nigromaculatis. 



Longitude, 9 mm.; latitude, 4 mm.; altitudo, 1.6 nun. — Budde-Lund, Crust. Isop. 

 Terrestria, 1885, pp. 210-211. 



''For characters of genus see Budde-Lund, Crust. Isop. Terrestria, 1885, p. 77, 

 and Sars, Crust, of Norway, II, 1899, p. 185. 

 28589—05 39 



