The Craspedosomatidas of Noy^th America. 41 



practically undistingnishable from those of the former species, 

 thus showing that variation in the genitalia proper does not af- 

 fect these neighboring structures, making their use as generic 

 characters desirable. 



According to Dr. Packard this is " what may be called a ' twi- 

 light' species, living in small caves in situations partially lighted." 

 In this connection it ought to be remembered that nearly all Dip- 

 lopoda are nocturnal and lucifugous. It would not be a surprise 

 to us if careful collecting in the neighborhood of the caves should 

 reveal many of the so-called species in dark corners and crevices 

 of rocks along with the open air species. There has been much 

 more careful collecting in the caves than outside. 



CLEIDOGOIVA gen. nov. 



CryptoMchus || Packard, Proc. Am. Phil. Soc. X_XI, p. 189 (1883). 



Spirostrephon Wood, not of Brandt; Pseudotremia Cope pjy.; Campodes Boll- 

 man, not of C. L. Koch. 



Ej^es well developed, of numerous (25-29) prominent ocelli arranged in 

 triangular patches. 



Antennse filiform, very long and slender; third joint longest. 



Mandibles with 12 pectinate lamellae. 



Promentum present, triangular. 



Segments with lateral carinee nearly obsolete; setigerous tubercles very 

 small. 



First two pairs of legs small and slender, the next fiA^e pairs in males mod- 

 erately crassate. 



Anterior male legs hispid on the interior face of the last joint. 



Genitalia of male of two pairs of processes, the posterior articulated with 

 the anterior at base. 



Ninth legs of male 5-jointed and clawed; two basal joints large, subequal in 

 length; three distal joints small, forming a hook. 



Tenth and eleventh legs of male with large coxal apertures; coxa of 

 eleventh leg with a conic process, the third joint unmodified. 



Pedigerous lamina of twelfth legs of male jjroduced at apex into a large 

 conic process directed cei^halad. 



Segments of adult 30. 



Distribution : Eastern States ; reported from Minnesota and 

 Arkansas ; thus far we have been unable to find it in western 

 Ontario, central New York, Long Island, Connecticut and the 

 eastern shore of Marjdand. 



That the affinities of Cleidogona are with Pseudotremia may 

 be inferred from the numerous characters common to both genera. 



