92 BRISTLE-TAILS AND SPRING-TAILS. 
tiful species that we have never noticed elsewhere, is our “ cricket 
on the hearth,” abounding in the chinks and crannies of the range 
of our house, and coming out like cockroaches, at night, shunning 
the light. Like the cockroaches, which they vaguely resemble in 
form, this species loves hot and dry localities, in distinction from 
the others which seek moisture as well as darkness. By some 
they are called “ silver witches,” and as they dart off, when dis- 
turbed, like a streak of light, their bodies being coated in a suit of 
shining mail, which the arrangement of the scales resembles, they 
have really a weird and ghostly look. i 
The Lepisma saccharina of Linnæus, if, as is probable, that is 
the name of our common species, is not uncommon in old damp 
houses, where it has the habits of the cockroach, eating cloths, 
tapestry, silken trimmings of furniture, and doing occasional dam- 
age to libraries by devouring the paste, and eating holes in the 
leaves and covers of books. 
In general form Lepisma may be compared to the larva of 
Perla, a net-veined Neuropterous insect, and also to the narrow- 
bodied species of cockroaches, minus the wings. The body is 
long and narrow, covered with rather coarse scales, and ends in 
three many-jointed anal stylets, or bristles, which closely resemble 
the many-jointed antennze, which are remarkably long and slender. 
The thermophilous species already alluded to may be described as 
perhaps the type of the genus, the L. saccharina being simpler in 
its structure. The body is narrow and flattened; the basal joints 
of the legs being broad, flat and almost triangular, like the same 
joints in the cockroaches. The legs consist of six joints, the tarsal 
joints being large and two in number, and bearing a pair of ter- 
minal curved claws. The three thoracic segments are of nearly 
equal size, and the eight abdominal segments are also of similar 
size. The trachee are well developed, and may be readily seen 
in the legs. The end of the rather long and weak abdomen is 
Pr opped up by two or three pairs of bristles, which are simple, not 
jointed, but moving freely at their insertion; they thus take the 
place of legs, and remind one of the abdominal legs of the Myria- 
pods; and we shall see in certain other genera (Machilis and Cam- 
podea) of the Bristle-tails that there are actually two-jointed bris- 
tles arranged in pairs along the abdomen. They may probably be 
directly compared with the abdominal legs of Myriapods. Further 
study, however, of the homologies of these peculiar appendages; 
