DIPLOPODA 471 



FAMILY 4. LYSIOPETALIDAE.* 



Like the Julidae, but with the first pair of legs only of the seventh 

 segment copulatory: 1 American genus. 



LYSIOPETALUM Brandt. Body long and slender, tapering gradually 

 to the hinder end; seventh antennal joint conical and very short: 1 

 American species; several in Europe. 



L. lactarium (Say) (Fig. 730). Body with about 

 60 segments and 115 pairs of legs, yellowish-brown 

 in color with mottled darker spots and bands; eyes 

 with 40 ocelli connected by a black band; length 35 

 mm.; width 2 mm.: common throughout the eastern 

 and central states. 



FAMILY 5. POLYDESMIDAE. 



(Fig. 726). Body more or less elongate, broad 

 and flattened, and with a hard integument, composed 

 of 19 or 20 segments and with 28 to 31 pairs of legs ; 

 the dorsal plate of each segment prolonged laterally 

 on each side to form a conspicuous wing; eyes absent; B W h?nd 

 antennae long; a row of stink glands on each side, body, 

 usually with a swelling around each ; anterior pair of 

 legs only copulatory on seventh segment of male: 9 American genera 

 with about 50 species, all of which can roll themselves together. 



Key to the genera of Polydesmidae here described: 



! Basal portion of leg without spines. 

 Z>! Anal segment pointed behind. 

 c x Dorsal plates flat. 

 di Each stink pore surrounded by a long, oval swelling ; each segment 



with 2 or 3 transverse rows of tubercles 1. POLYDESMUS 



d a Each stink pore surrounded by a round swelling ; each segment with 



4 or 5 rows of tubercles . . . , 2. SCYTONOTUS 



c. Dorsal plates convex and smooth 3. LEPTODESMUS 



6 2 Anal segment quadrate and smooth, or nearly so 4. EURYURUS 



a a Basal portion of legs with spines 5. FONTARIA 



1. POLYDESMUS Latreille. Male with 30, female with 31 pairs of 

 legs; each segment with 2 or 3 transverse rows of distinct tubercles; each 

 stink pore surrounded by an elongated swelling; lateral plates large and 

 horizontal in position: 9 American species. 



P. serratus Say (P. canadensis Newport). Body brown, often red- 

 dish in color, about 37 mm. long; each dorsal plate with 2 rows of 4 

 rectangular tubercles in each; terminal spine of male copulatory ap- 

 pendage hook-shaped: common in the eastern and central states. 



* See "A Revision of the Lysiopetalidae," by A. S. Packard, Proc. Am. Phil. Soc., 

 Vol. 21, p. 177. 



