POLYDESMHXE. 677 



on decaying vegetable matter, or tube-like, as in Brachycybe 

 and allies, the parts being converted into a tube or beak. 



GLOMERID^: Leach. In this group the eyes are arranged in 

 a linear series, and the antennae are placed on the front of the 

 head. The body is half-cylindrical, short and plump, with from 

 twelve to thirteen segments. The head is large and free, with 

 the first thoracic ring small, while the last abdominal ring is 

 large and shield-shaped. The genital openings in both sexes 

 are situated just behind the insertion of the second pair of 

 limbs. In Glomeris the body consists of twelve rings and 

 seventeen pairs of limbs, while in Sphcerotherium the body is 

 made up of thirteen rings and twenty-one pairs of feet. The 

 species are exotic, Glomeris marginata Latreille being found 

 in Europe, and the Sphaerotheria in the tropics. 



POLYDESMID^E Leach. In this group the body is much flat- 

 tened, the sterna overarching the scuta, to which they are 

 closely cemented, and the scuta are furnished with lateral 

 laminae. "The head is large and massive, the absence of eyes 

 and the small antennae point to a state of low development of 

 the special senses. The female genitalia are placed in the 

 third segment, just posterior to the second pair of legs. They 

 are generally more or less hidden within the body ; 

 the male organs are situated in the seventh segment, 

 replacing the eighth pair of legs. They generally 

 project very prominently from the body." The young 

 have three pairs of legs, on the 2d, 4th and 5th rings. 



In Polydesmus the body is much flattened, with broad ^ 

 lateral expansions to the rings. Polydesmus Cana- 

 densis Newport is deep brown, with pubescent scarcely 

 clavate antennae ; each of the scuta has eight scales, 

 arranged in a double series. The male appendages Fig. 649. 

 are hairy, with a curved terminal spine of moderate length. 

 The female appendages "consist of a pair of bodies shaped 

 somewhat like the crest of a helmet. Along their free margin 

 is an opening surmounted b}^ a double series of teeth-like pro- 

 cesses. It is found in the Northern and Middle States. P. 

 erythropygus Brandt (Fig. 649) inhabits the Middle and 



