CHILOPODA. 597 



Normally they possess seven segments, a coxa, trochanter, 

 femur, tibia, and three tarsalia the last of which ends in a claw. 

 The legs of the last pair (anal legs) are attached to the ante- 

 penultimate (pregenital) segment and are usually longer than 

 the preceding. The genital segment (see above) carries the 

 median generative opening and usually a pair of genital ap- 

 pendages. The latter are better developed in the female, in 

 which they are used in oviposition. They are absent in female 

 Scolopendridae and in many male Lithobiidae. The anal 

 segment is much smaller than the others and is without 

 appendages. 



Glands are found in the coxal joints of the last four or five 

 pairs of legs (coxal glands) ; in the pleura of the last pedi- 

 gerous segment ; in the sternites of the segments (sternal 

 glands) and in the anal segment (anal glands). The secretion 

 of the sternal glands causes the phosphorescence found in 

 some Geophilidae. The ventral pits are paired or unpaired 

 pits found on certain 'of the sternal plates of some genera (some 

 Geophilidae) . 



Of sense organs, besides the sensory hairs and spines of various 

 forms found on the body generally and on the appendages, 

 especially the antennae and jaws, may be mentioned the maxillary 

 organs of Scutigera. These consist of a pit, richly lined by 

 setae and supplied by a special nerve, on the inner side of each 

 of the basal portions of the 1st maxillae. An organ of Tomosvary 

 covered with hairs and similar to that of Diplopoda (p. 586) can 

 very generally (apparently absent in Geophilidae) be made out. 

 It is placed near the base of the antenna, and is supposed to be 

 auditory in function. The eyes are simple ocelli, similar to 

 those of Diplopods and Insects (p. 328). In Lithobius they are 

 very closely aggregated. In Scutigera there are compound eyes, 

 which are sometimes called pseudo-facetted eyes. They are, 

 however, true compound eyes resembling in all essential points 

 of structure those of Insects and Crustacea. 



The alimentary canal consists of fore-gut or oesophagus 

 (stomodaeum) lined by chitin ; of mid-gut or enteron proper 

 without chitinous lining ; and of hind-gut .or rectum (procto- 

 daeum) which is lined by chitin and receives at its anterior end 

 two long malpighian tubes. In the Scolopendridae and 

 Geophilidae the oesophagus is of considerable length and the 



