MITES— CENTIPEDES — MILLIPEDES 207 



Tetranychus telarius, which is scarcely recognisable without a microscope, is covered 

 with tine hairs, and of a pale yellow colour, with a darker spot on each side of 

 its oval-shaped abdomen. Its larva is probably the so-called autumn grass-mite 

 (Leptus autumnalis), a six-legged creature, which appears in two phases during July 

 and August, on grasses, corn, elder, and gooseberry bushes, and produces small 

 itching sores on the human skin. One of these phases is slow in its movements 

 and of a light honey colour ; the other runs quickly and is bright red. 



The centipedes (Chilopoda) are without wings, and breathe 

 through tracheae, but the head is distinctly marked off from the 

 body, which is composed of many successive segments of similar shape, to almost 

 every one of which is a pair of legs. The mouth is provided with toothed 

 cutting jaws, and the head with a pair of many-jointed antennae. Centipedes 

 are nocturnal, shunning the light, and living on insects which they kill instantan- 

 eously by means of a poisonous fluid secreted at the base of a long fang. Their 

 commonest European representative is the worm-like centipede (Geophilus 

 electricus), which is of a pale yellow colour, has about seventy-one pairs of legs, 

 and is about 1^ inches long, but only -Jj- of an inch broad. This species is 

 noteworthy as being luminous. In an allied group we may mention, as the best 

 known, the brown stone-creeper, Lithopius forficatits, nearly an inch long, and 

 an eighth of an inch broad, with from thirty-eight to forty-eight joints in its 

 antennae and fourteen pairs of legs. It is of a greyish brown colour, and lives 

 under the bark of trees and in the mould in gardens, and is noticeable for the way 

 in which flies are instantly killed by its bite. 



The pigmy centipedes (Symphyla) form a group by themselves; they are 

 small, delicate creatures, with a pair of legs only on the larger segments of the 

 body, and live in cool and damp places in forests, gardens, and fields under leaves, 

 stones, and loose ground, their food probably consisting of small insects. 



Another allied group is the Pauropoda, so called on account of their having 

 comparatively few (eighteen) legs. These small arthropods avoid the light and 

 dwell in damp, muddy places ; among them may be mentioned Pauropus huxleyi, 

 which is probably found all over Europe. It is T V of an inch long, or a little more, 

 with a smooth, snow-white, glistening body. 



The millipedes (Diplopoda), which are better known and more 

 numerously represented than either of the preceding groups, are 

 sluggish animals which shun the light and live principally on decaying plants. They 

 have cylindrical bodies, and bear on some of their segments two pairs of legs. The 

 common millipede {lulus terrestris), often called a centipede, which is the best 

 known species, lives under moss and stones, and has a narrow but extraordinarily 

 long body, black and grey in colour, with two yellowish lines along the back. 

 In another species (Polydesmus complanatus), which lives under dead leaves, the 

 body is also long and narrow, but flattish and sharp-edged. It is of a brownish 

 grey colour, and the numerous segments are uneven in the middle, the last being 

 pointed. Yet another species (Glomeris pustulata), often fStmd in forests beneath 

 stones, is blackish grey, with yellow edges to the body-segments, each of the first 

 four segments having four small yellowish red spots, but the others only two. 



