THE FAMILY GOMPRODESMID^—COOE. 689 



not accommodiited by an excavation; (irst segment with distinct, tliough ronuded, 

 lateral sides and posterior corner, the marginal callus thickened as in other seg- 

 ments 



Copulatory legs with two large, slender spines rising from the median face of the 

 nodus; one of these is bent laterad around the base of the flagellum; first segment 

 'proportionately long and narrow^ its cariu;e not equaling those of the second seg- 

 meet: Genus Sigodesmus, p. 722. 



Copulatory legs without conspicuous spines from the mesial side of the nodus at 

 the base of the tlagellum; first segment with carime produced to equal or exceed 

 those of the second segment: Genus Jstrodesmus, p. 726. 



Tlie geuus Merodesnms, being known only from the female, could 

 not be satisfactorily tre<ited in a synopsis in which the secoudary 

 sexual characters of the male play such an important part. Whether 

 the females will also offer characters throughout the family can hardly 

 be inferred as yet, for out of the fourteen genera thus far established 

 females of only four are known, over three-quarters of the mature spec- 

 imens extant in collections being males. As far as Merodesnms is con- 

 cerned, however, it can not well be the female of any of the genera to 

 which it might be supposed to be related, the long cylindrical hirsute 

 processes of the coxtxi of the second pair of legs separating it from 

 Astrodesmus, the only other large genus with 10 olfactory cones. 



ULODESMUS, ne^A^ genus. 



Body rather small, over five times as long as broad, oblong, tapering 

 broadly at the ends; dorsum strongly convex, the narrow carinre de- 

 curved nearly in the direction of the dorsal arch. 



Antennas (f). 



First segment nearly half as long as broad, subreniform; margins 

 converging laterad; lateral edge short and broadly rounded. 



Segments distinctly rugulose. 



Lateral carinaj with lateral margins strongly developed, thick and 

 prominent; margins of anterior segments distinct but much less devel- 

 oped, those of the first segment scarcely thickened laterad; posterior 

 corners of carinas scarcely produced on posterior segments. 



Repugnatorial pores 13, located in large and deep depressions facing 

 nearly laterad; the marginal callus is strongly thickened to accommo- 

 date the poriferous depression, that of the poreless segments being 

 scarcely more than half as thick. 



Preanal scale rounded triangular, bluntly apiculate, the setiferous 

 tubercles small, not projecting beyond the anterior margin. 



Sterna without transverse ridges. 



Sternum of sixth segment of male with two broadly rounded laminate 

 processes between the bases of the anterior pair of legs. 



Sternum of fifteenth segment of male unmodified. 



Legs of males moderately crassate, the anterior with a small fleshy 

 sole and claws not much reduced, the second joint prominent dorsad, 

 but not so prominent as in the larger forms. 

 Proc. N. M. vol. xxi 44 



