The Graspedosomatidse of North America. 55 



of the four distal joints. Indeed, this idea becomes reasonably 

 probable when we consider that there is a claw in Scoterpes, and a 

 similarly located chitinous bunch in Zygonopus and Trichopeta- 

 lum, which may be interpreted as the rudiment of a claw. It 

 should also be noticed that in Pseudotremia and Cleidogona 

 there is evidently a tendency toward the development of two large 

 proximal joints at the expense of the distal. 



SCOTERPES Cope. 1872. 

 Am. Nat.- VI. p. 414. 

 Spirostrephon {Pseudotremia) Packard and Ryder, not Brandt. 

 Craspedosoma {Scopterpes) LatzehMyr. Oest. Ung. Mon. II., p. 209 (1884); 



Haase: Zeitsch. f. Entom., N. F., XI., p. 60 (1886). 

 Eyes wanting. 



Antennae of moderate length, third joint longest. 

 Segments with moderately prominent shoulder-like carinse. 

 Ninth pair of legs of male two-jointed, the distal joint with a strong claw. 

 Segments of adult 30. 



The single species of this genus is from Mammoth Cave. It 

 is known to us only from descriptions and figures, but there can 

 be little doubt of its close relationship with Z3'gonopus and 

 Trichopetalum, from both of which it is distinct in the large claw 

 of the ninth legs of the male. We reproduce Dr. Packard's fig- 

 ures of the genitalia and ninth pair of legs, but it is not possible 

 to get from these or from his descriptions a satisfactory idea of 

 these structures, nor one which will enable us to compare them 

 with allied forms. Indeed, we are not certain that the ninth legs 

 of males ought not to be spoken of as three-jointed. In Dr. 

 Packard's figure they appear entirely detached, and if the two 

 joints are correctly drawn another would seem necessary to con- 

 nect them with the body. 



It is in this genus that the six dorsal bristles peculiar to the 

 present family have their greatest development. According to 

 Drs. Cope and Packard these bristles approximate in length the 

 diameter of the body, giving the animal very much the appear- 

 ance of a caterpillar. 



Scoterpes copei (Packard) Cope. 

 Spirostrephon {Pseudotremia) copei Packard: Am. Nat. V., 748 (1871). 

 Scoterpes copei (Packard) Cope: Am. Nat. VI., p. 414 (1872) ; Packard: 

 Proc. Am. Phil. Soc. XXI., p. 193 (1883) ; McNeill: Bull. No. 3, 

 BrookvilleSoc, p. 8 (1888). 



Plate I., figures 12-13. 



