604 



CLASS III. MYRIAPODA. 



placed in the dorsal middle line. They occur at the hinder edge of the 7 

 anterior of the 8 tergites above mentioned. They lead into tracheal 



sacs from which 

 tufts of tracheae 

 (without spiral 

 fibre) project into 

 the pericardium 

 and aerate its 

 blood. The heart 

 therefore receives 

 arterial b 1 o o d. 

 Genital appen- 

 dages are present 

 in both sexes. 

 The young when 

 hatched do not 

 possess the full 

 complement o f 

 legs. They are 

 very active 

 animals. T h e y 

 are found in the 



From the Encyclopaedia Britannica. 



FIG. 362. A Scutiqera rubrolineata (after Buffon). B Tergite and 

 part of a second terpite of the same, enlarged to show the position 

 of the stigmata o ; p hinder margin of tergum. 



warmer regions all over the world, under stones, etc., and especially in 

 human dwellings. Sr.utigera Lamarck, Sc. colcoptratn L. r Central and S. 

 Europe. 



Order SYMPHYLA.* 



Small progoneate forms with 12 pairs of legs and a head possessing 

 antennae, mandibles, maxillulae, maxillae and labium. 



The Symphyla are small Myriapods, less than three mm. 

 in length. They possess a distinct head, and a body which in 

 being flattened dorso-ventrally recalls that of the Chilopoda. 

 The body (Fig. 363) consists of 12 leg-bearing segments and of 

 an apodal terminal segment, and of 12 apodal segments inter- 

 calated between these, so that there are 25 segments in all, 

 behind the head. Sixteen (or fifteen) of these segments possess 

 well marked dorsal scuta (Fig. 363), of which the first, which 

 carries the first pair of legs, is the smallest. The legs are not- 

 grouped in pairs and there is no diplopody. 



* Gervais P., Myriapodes, in Walckenaer, Hist. Nat. des Insectes Apteres, 

 iv, Paris, 1847^ Newport G., Monograph of the class Myriapoda, order 

 Chilopoda, Trans. Linnean Soc., 19, 1845, p. 373. Latzel R., op. cit., 

 1884. Ryder J. A., Structure, affinities arid species of Scolopendrella 

 Proc. Acad. Nat. Sci. Philadelphia, 1881, p. 79. Grassi B., I progenitor! 

 degli Insetti e dci .Myriapodi, Morfologia delle Scolopendrelle, Mem. d. 

 Reale Accad. d. Scienze d. Torino (2), 37. 1886. Schmidt P., op. cit. 

 Hansen H. J., The genera and species of the order Symphyla, Q.J.M.S., 

 47, 1903, p. 1. 



