306 ENTOMOLOGY FOR MEDICAL OFFICERS 



4. Symphyla {crw = connecting ; <^vKov = clan ; signifying 

 that in some respects they appear to connect the Centipede 

 clan with the Insect clan). Minute Myriapods with twelve 

 pairs of legs which end in two claws like those of insects. 

 They resemble tiny Centipedes in form and in having two 

 pairs of maxilljE ; but, as with Millipedes, the genital opening 

 is close behind the head. 



Order Chilopoda : Centipedes (Gr. xetAo? = a lip ; ■7rouy = foot). 



In Centipedes the body consists of a head, and usually of 

 a large number of flattened segments, all of which except the 

 two last are alike. The head carries a pair of antenna, 

 which as a rule are composed of very numerous segments ; a 

 pair of toothed mandibles, and two pairs of maxillae, the 

 second pair of which have their bases united to form a lower 

 lip, or labium. Eyes are generally present, and in most 

 cases consist of two groups of ocelli placed one on each 

 side of the head. 



Of the segments behind the head the two last are small 

 and are a good deal tucked in ; the anus opens on the last 

 and the genital duct on the last but one, and neither of them 

 has appendages. But all the other segments carry each a 

 pair of legs, all of which except the first and last are alike, 

 and are composed of seven pieces and a terminal claw. The 

 first pair of legs differ from all the others in the large size of 

 the basal pieces, the enormous development of the claw, and 

 the reduction of the other pieces. These legs are known as 

 " poison-claws," or as foot-jaws (maxillipeds), since their bases 

 are fused with the sternum of their proper segment to form a 

 sort of additional lower lip ; the enormous claw is perforated 

 near the tip, like the fang of a serpent, to give exit to the 

 venom, which is secreted by a gland in the base. The last 

 pair of legs differs from all the others in being considerably 

 longer, and occasionally in being also flatter and broader. 



The female Centipede as a rule produces eggs, and often 

 guards them until they are hatched. The new-hatched young 

 sometimes resembles the parents, but sometimes has fewer 

 legs. 



Centipedes live under stones, dead leaves, and other kinds 



