MILLIPEDES. 
2 I I 
Zephroniodesmus, occurring in Sumatra. Xone of tlie species exceed a quarter of an 
inch in length. 
In the Helminthomorpha, or worm-like millipedes, which comprise the majority 
of the species, the body is composed of from nineteen to over ninety segments, is 
usually elongate and slender, and capable of being spirally coiled. The characters 
by which this group may be distinguished from the two preceding are that the last 
tergal plate forms a complete ring, enclosing the pair of valves and sternum, and 
that the tracheal plates take the form of two median sternal pieces, to which the 
legs are directly articulated. Moreover, the pleural scutes, although sometimes free, 
are less distinct than in the preceding groups. The order is divided into the sub¬ 
orders Colobognatha, Chordeumoidea, Callipodoidea, Iuloidea, and Polydesmoidea. 
In the first of these the mandibles have undergone great degeneration, and in the 
most modified forms ( Siphonophora ), the lower edge of the head (labrum) and the 
lower lip (gnathochilarium) are together produced into a long, piercing snout. The 
pedal laminae, or sterna, are always free and movable, as are rarely the pleurae. 
The secreting pores are present on all the segments, with the exception of the first 
four and the last; the parts of the segments around the pores being sometimes 
produced into wide plate- or rod-like processes covering the legs. The body 
segments vary in number from about thirty to over seventy, although the largest 
members of this group seldom exceed an inch in length, and are generally shorter. 
These millipedes occur in the tropical countries of both hemispheres, one form 
(Polyzonium germanicum ) extending into Central Europe. In the Chordeumoidea 
there are no excretory pores, but each segment bears six symmetrically-arranged 
bristles. There are usually either thirty or thirty-two body segments; the pedal 
lamime are always free, and often the tergal plate is keeled, or furnished with a 
large lateral pro¬ 
cess on each side. 
There is a pair of 
eyes on the head, 
and the jaws are 
normally devel¬ 
oped. 
The Iuloidea, 
which is the largest 
suborder of the 
worm-like milli¬ 
pedes, contains 
families which may 
be distinguished 
from the last group by having the pedal laminae united to the terga. Some of 
the tropical species reach 6 inches or more in length, and are the largest millipedes. 
Of the families, the Spirostreptidce are spread over all tropical countries, but 
scarcely migrate into temperate climes; while the Iulidce reach their maximum 
development in Europe and the United States, and are only sparsely represented 
in the Tropics. The Cambalidce are remarkable for the presence of crests and 
tubercles on their segments. 
millipede, lulus sabulosus (enlarged twice). 
