TR A CHE ATA 315 



number of segments. Some members of the family Geophilidae 

 are phosphorescent, and secrete from certain glands on the 

 ventral surface a luminous slime ; since this is produced by 

 both male and female, and neither of them has eyes, the 

 secretion is regarded as a means of frightening or warning off 

 enemies. The male GeopMlus spins a web, and drops a sperma- 

 tophore in the middle of it, and the female comes and fertilises 

 herself. GeopMlus longicornis is common in Britain; the 

 female coils herself up and sits on her eggs, and is stated not 

 to leave them until they are hatched. Cryptops hortensis, with 

 twenty-one pairs of legs, is also British. 



Scutigera has very long antennae and legs, the latter in- 

 creasing in length at the posterior end (Fig. 179). This genus 

 has facetted compound eyes, and its tracheal system is peculiar ; 

 the stigmata are median and dorsal, one for each segment, 

 opening in a notch at the posterior edge of each tergum. 

 Certain species produce a rattling noise by rubbing their legs 

 together. ' 



Order 2. DIPLOPODA (Chilognatha). 



Chaeaotekistics. — TJie memhers of the second sub-order of the 

 Myriapoda are characterised hy their bodies leing cylindrical 

 or subcylindrical, and their antennae short, of seven segments 

 only. Except at the anterior end, the segments tear two pairs 

 of legs, and the bases of the legs are near together ; there are 

 also two pairs of stigmata on every segment. The generative 

 aperture is at the base of the second or third pair of legs. 



Fig. 180. — Ventral view of Polyxenvs lagurus (after Bode) mucli enlarged, actual 

 length a little over ^th of an inch. 



a. Position of genital openings. 



The Diplopoda are all vegetable feeders, and have no 

 poison claws. The genus Polyxenus is somewhat intermediate 



