128 BRISTLE-TAILS AND SPRING-TAILS. 



beautiful 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 also in closets, where it 

 feeds on sugar, etc., and comes out like cockroaches, at night, 

 shunning the light. Like the cockroaches, which it vaguely 

 resembles 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 disturbed, like a streak of light, their bodies 

 beiqg coated in a suit of shining mail, which the arrangement 

 of the scales resembles, they have really a weird and ghostly 

 look. 



The most complicated genus, and the one which stands at the 

 head of the family, is Machilis, one species of which lives in 

 the Northern and Middle States, and another in Oregon. They 

 affect damp places, living under leaves and stones. They all 

 have rounded, highly arched bodies, and large compound eyes, 

 the two being united together. The maxillary palpi are greatly 

 developed, but the chief characteristics are the two-jointed 

 stylets arranged in nine pairs along each side of the abdomen, 

 reminding us of the abdominal legs of Myriopods. The body 

 ends in three long bristles, as in Lepisma. 



The Lepisma saccharina of Linnaeus, 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 

 damage 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 antenna, 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 flat- 

 tened; 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 terminal curved claws. The 



