128 
Guide to Myriopoda. 
Table-case approximately upon alternate segments, the terga without stigmata 
No. 28. being greatly reduced in size. 
The young, upon hatching, have only seven pairs of legs, the 
remaining eight being added with successive moults. 
The Lithobiomorpha are swift-footed centipedes, which live 
under stones or fallen tree-trunks, and feed upon worms, insects, 
etc. They do not attain to any great size. 
There are about half-a-dozen British species of Lithobius ; 
perhaps the commonest of them is 
Lithobius forficatus. 
Sub-class 
ANARTIOSTIGMA. 
The normal tracheal system is 
replaced in the Anartiostigma by a 
series of median dorsal pulmonary 
sacs, furnished with tubes dipping 
into the pericardial space, and open- 
ing each by a single stigma which 
results from the upward migration 
and coalescence of the normal pair 
of stigmata upon the first, third, fifth, 
eighth, tenth, twelfth, and fourteenth 
segments. The remaining segments 
do not bear stigmata, and their dorsal 
plates are reduced or absent, that of 
the seventh disappearing completely. 
The antennae are very long and 
filiform ; the legs, of which there are 
fifteen pairs, as in the Lithobio- 
morpha, are also very long, and have 
the terminal segments many- jointed. 
The Scutigeridae (Fig. 90), the 
only family of the Sub-class, reach 
their greatest size in the tropics, and are quite unknown in north 
temperate and Arctic countries of the world. Most of the 
members of the order are of rather small size, but one or two of 
the Oriental species ( Scutigera longicornis, etc.) reach a length of 
several inches. They live on insects, and are remarkable for 
their extreme swiftness of foot. They also have a habit, when 
pursued or seized, of dropping their legs. Hence it is exceedingly 
difficult to capture undamaged specimens. 
Fig. 90. 
Scutigera ( Cermatia ) forceps (after 
Kingsley). 
