DIPLOPODA 469 



body; third segment usually legless: 7 American genera and about 50 

 species, all of which can roll themselves together. 

 Key to the genera of Julidae here described: 



o x Third segment without legs. 

 &! Mandibular teeth 4. 



c x Only the ventral plates of the first 2 segments free 1. JULUS 



Cj All the ventral plates free 2. NEMASOMA 



& 3 Mandibular teeth 10 3. PARAJULUS 



a a Third segment with legs. 



&! All 4 anterior segments with legs . . .4. SPIBOBOLUS 



& a Fourth segment without legs 5. CAMBALA 



1. JULUS L. Eyes, if present, composed of a number of ocelli; 

 third segment without legs; first pair of legs of male 3-jointed, very 

 small; antennae delicate; copulatory legs of male usually hidden; only 

 the ventral plates of first segments free ; inandibular teeth 



4: about 10 American species. 



J. virgatus Wood (Fig. 727). Body yellowish-brown, 

 with a median and 2 lateral bands; eyes distant, composed 

 of 25 to 40 ocelli on a side; segments 30 to 35; legs 50 to 

 65 pairs; last segment rounded; length 12 mm.; width 1 

 mm. : common all over the country, especially in meadows ~ in ?w5od)* 

 and gardens. 



J. venustus Wood. Color reddish-chestnut, lighter in young speci- 

 mens; segments 52 with usually two black dots on each side of each 

 segment ; last segment mucronate ; length 2 cm. : common in eastern and 

 central states. 



2. NEMASOMA Koch. Similar to Julus, but all the ventral plates 

 free: 2 American species. 



N. minutum (Brandt). Body brown, with a lateral row of ovate 

 black spots in each side, composed of 35 to 45 segments, 12 mm. long, 

 .8 mm. wide; feet pale, not extending beyond the body; eyes distinct, 

 with a dark band between them and with 8 or 9 ocelli on a side : common 

 in eastern and central states. 



3. PARAJULUS Humbert and Saussure. Eyes composed of numerous 

 ocelli; third segment without legs, second pair very small; first pair 

 in males 6-jointed; mandibular teeth 10; number of segments 40 to 

 70, last segment more or less prolonged into a spine: 13 American 

 species. 



P. impressus (Say). Body not hairy, chestnut brown, with a mid- 

 dorsal line and 2 lateral rows of black spots and composed of 45 to 55 

 segments, 32 mm. long and 2 mm. wide; 70 to 90 pairs of feet, sparsely 

 hairy; the first pair very large; ocelli 40 to 60 on a side; terminal spine 

 short: central and eastern states. 



