44 CENTIPEDES 



The Lithobiomorpha are distinguished from the Scolopendro- 

 morpha by having the body composed of 15 leg-bearing somites, of 

 which only six or seven possess spiracles, the terga of those with- 

 out spiracles being greatly reduced in size. The basal segments of 

 the legs are somewhat enlarged and the antennal segments number 

 from 20 to 50. The centipedes of this order are referred to three 

 families: Lithobiidae, Henicopidae and Cermatobiidae. They are 

 mostly of small size, the largest being the continental Lithobius 

 fasciatus. Several species oi Lithobius are common in England, the 

 best known being the large L. forficatus. Nearly as large is L. 

 variegatus which is easily recognised by its attractive variegated 

 colour pattern. This species is of interest because it is found only 

 in the Channel Islands and Britain, where it occurs mostly in 

 southern counties. We also have one species of Henicopidae, 

 Lamyctes fulvicornis, a small form distinguishable from Lithobius 

 spp. by the presence of a single pair of ocelli instead of many, and 

 by the presence of spiracles on the first leg-bearing somite. The 

 Cermatobiidae resemble the Henicopidae in many characters and 

 are noteworthy on account of the absence of pores on the last pair 

 of legs and the long, thin, many-segmented antennae. These 

 characters tend to link them with the Scutigeromorpha. The 

 genus Cermatobius is found in the Moluccas. 



The remaining order, the Scutigeromorpha, is sometimes placed 

 in a separate sub-class, the Anartiostigma, represented by a single 

 family, the Scutigeridae. Its representatives are remarkable for 

 the extraordinary length of their limbs and for their extreme 

 agility. They are medium-sized centipedes having fifteen pairs of 

 legs and sternal plates, but only eight tergal plates. Their eyes are 

 compound and bulging, the antennae widely separated at the base 

 and exceedingly long. The spiracles leading into sacular, tufted 

 tracheae are unpaired and open dorsally upon the first seven ter- 

 gites. These animals are found in all warm tropical and temperate 

 countries, the largest, Scutigera longicornis and S. clunifera, occur- 

 ring in India and southern China and reaching two or three inches 

 in length of head and body. There are no indigenous British 

 species, but S. coleoptrata, common in southern Europe, was once 

 introduced into a paper-mill in Aberdeen where it succeeded in 

 establishing itself. 



