MILLIPEDES. 



SUMATRAN PILL-MILLIPEDE. SphfXOpceUS (nat. size). 



the antennae are seven- jointed, and the body is not furnished with tufts of scale-like 

 hairs. The group is divisible into the orders Oniscomorpha, Limacomorpha, and 

 Helminthomorpha. In the former, as represented by the pill-millipedes, the body 



is short and broad, convex above and flat 

 below, with the second and last segments 

 enormously enlarged, and capable of being 

 rolled up into a ball. The skeletal pieces 

 which compose the segments are distinct and 

 movably jointed together. Each typical 

 segment consists of seven pieces ; a large 

 and vaulted tergum forming the upper sur- 

 face and concealing the legs ; while beneath this on each side there is a small pleural 

 piece, and between this and the two legs two still smaller tracheal plates bearing the 

 stigmata. The legs are in contact in the middle line of the body, and those of the 

 last pair are enlarged in the male and transformed into a pair of clasping organs. 

 Of the two families into which the order is divided the Glomeridce, or small pill- 

 millipedes of Europe, have the antennae close together upon the front of the head 

 the eyes with a single row of ocelli, and the 

 body consists of only twelve segments. In 

 the Zephroniidce, or large tropical pill- 

 millipedes, the antennae are situated on the 

 sides of the head, the eyes are composed of 

 a spherical cluster of ocelli, and the body 

 consists of thirteen segments. In the South 

 African genus Sphcerotherium the last 

 pair of legs in the male is furnished with 

 a well developed stridulating apparatus, 

 consisting of a finely ridged plate, which 

 by being rubbed against a set of granules 

 on the inner surface of the last tergal shield, 

 gives rise to an audible sound. Although 



no representatives occur in America, the order is spread over the Eastern Hemi- 

 sphere, the Glomeridce ranging over Europe and thence into India and Borneo, while 

 the Zephroniidce occur in South Africa, Madagascar, India, the Malay Peninsula, 

 Australia, and New Zealand. 



The Limacomorpha, or slug-like millipedes, form a small group, containing but 

 two known genera and three species included in the family Glomeridesmidce. 

 The body is composed of nineteen or twenty segments, all of them being approxi- 

 mately equal in size and similar in form, and none of them abruptly larger than the 

 rest. The body is capable of being spirally coiled ; its segments are formed 

 much as in the Oniscomorpha, but the tracheal plates are not distinct. The last 

 tergal plate, although small, forms a hood which covers over the last pair of legs, 

 and these are modified in form as in the males of the Oniscomorpha. The rest of 

 the legs are composed of only six segments, the basal of which is much enlarged. 

 There are no true eyes. Glomeridesmus, the typical genus, is known from two 

 species, found respectively in New Granada and in St. Vincent ; the other genus, 



ENGLISH PILL-MILLIPEDE (nat. size). 



