— 147— 



Family l. POLYXENIDAE Gray and Jones. 

 This family contains the single genus Polyxeniu Latr , of which we 

 have one species P . fascieulatus Say, distributed from Massachusetts to 

 Georgia. 



Family 2. POLYZONIDAE Gervais. 

 This family contains four American genera with rive species; the 

 genera may be distinguished as follows: 



A. -Sixth and seventh joints of antennae confluent with the fifth and with it forming 



a club; body segments 56 Andrognathus Cope.* 1 sp 



Joints of antennae normal, not forming a club B 



B. — Eyes wanting; rostrum shorter than the antennae. . . .Brachycybe Wood.** 2 sp 



Eyes present, conspicuous C 



C. —Eyes 8; body segments about 45 Octoglena Wood. 1 sp 



Eyes 2; antennae large and stout; body segments 50-53 



Petaserpes Cope. 1 sj 

 Family 3. POLYDESMIDAE Leach. 

 The Polydesmidae of this country have all been described under 

 Polydesmus Latr. f of which twenty-one species are recorded. Strongylo- 

 st ma Brandt, Fontaria Gray and perhaps other groups ranked as sub- 

 genera by Wood, will take generic rank; until, however, a careful study 

 of the types can be made it will be best to leave the species in the orig- 

 inal genus under which they have been described. 



Family 4. CHORDEUMIDAE C. Koch. 

 With some hesitation I place in this family most of the forms hitherto 

 ranked as Lysiopetalidae by American writers. In this I follow Dr. Latzel 

 whose important work has been noticed above. In a note on the American 

 Chordeumidae\\ he unites Scoterpes Cope and Zygonopus Ryder and places 

 them as a subgenus of Craspedosoma Leach-Rawlins. Trichopetalum 

 Harger he also regards as forming part of Craspedosoma, and Pseudotremia 

 Cope, he would place near the same genus Cryplotrichus Packard, he 

 places near Campodes Koch. The form of "Polydesmus with eyes" re- 

 cently described by Packard,^ Latzel|J states is properly one of the 



* Forming according to Cope (Proc. Amer. Philos. Soc. XI, 182) the type of a 

 new family Andrognathidte. 



** Latzel unites Brachycybe Wood with Platydesmus Lucas. The latter genus 

 has priority. 



t An apparent exception is Stenonia hispida Sager, Proc. Phila. Acad. VIII, 

 109 (1856). This undoubtedly belongs to Polydesmus though the description is very 

 imperfect. 



ft Lie Myriapoden der Oest.-Ungar. Monarchic, II, pp. 213 — 214 (1884). 



t American Naturalist XVII, 428 (1883). 

 Xt Latzel, loc. cit. p. 125, note. 



