PEACH. ROOT SOW-BUGS. 117 



obliterated after the worm has left it, but remdns often for years 

 afterwards, and forms a favorite abode for those pseudo-insects 

 which are commonly designated sow-bUgs or wood-lice. When 

 one of these old burrows of the borer is examined, these little 

 animals will commonly be found huddled together withiq it, and 

 covering the sides of the cayity as closely as they can stand. And 

 on digging around the root of a peach tree at any time several of 

 them will commonly be found. As no notice of our American 

 species of these creatures has ever been published, that I am 

 aware, some account of them may appropriately be given in this 

 connection. 



Th^se animals are popularly known in dififerent countries under 

 the names of millipedes, wood-lice, hog-lice, slaters or sclaters, 

 and sows. In this section " sow bugs" is the popular name in- 

 varial)Iy given to them, whilst the name wood-lice would here be 

 understood as designating the wood-tick, Ixodes ^meiicanus, and 

 its kindred species, and millipede would be regarded as a synonym 

 of centipede or " thousaud-legged worm," a species of Julus or 

 Scolopendra. The sow-bugs were ranked as insects by the older 

 naturalists, but by most writers at the present day they are 

 grouped with the lobster, crab, craw-tish, hoise-hoof, &c., in a 

 distinct class, which is named Crustacea, in allusion to the hard 

 shell-like crustaceous covering which forms the exterior coat 

 in most of the species. They ditfer from true insects essen-^ 

 tially in their breathing apparatus, which is a kind of gills of a 

 pyramidal form, and made un of thin plates or short threads 

 placed on the under side of the body, commonly at the base of 

 the legs. Insects, on the other hand, respite through spiracles or 

 breathing pores, placed in a row aLmg eacii side of the bc^dy, 

 through which, by small pipes, air is admitted into two priiic pal 

 tubes which run parallel to each other, and are. extended the 

 whole length of the body. The crustaceans, like insects, have 

 jointed antennse and legs, and. the body composed of a number of 

 segments connected by transverse sutures, but they differ from, 

 most insects in being destitute of wings, and in undergoing no 

 metamorphosis, the young when first hatched having the same 

 form aud parts which belong to it when mature. In this class 



