32 MILLIPEDES 



plies to Oxidus gracilis in particular. The ventral surface of the 

 posterior 13 or 14 body somites of the male is parallel and dorsal to 

 the anterior 10 or 1 1 body somites of the female and the legs of the 

 male on these somites are bent closely around the female. In the 

 region of the eighth, ninth and tenth somites the body of the male 

 is twisted half around the female so that his gonopods are in con- 

 tact with her vulvae which open on the third body somite. The 

 head and thorax of the male are directed anteriorly and bent over 

 the head of the female which is held by his seven anterior pairs of 

 legs. Bright light or handling usually causes a pair to separate: but 

 if undisturbed copulation may occur several times and last for 

 several hours (Causey, 1943). 



Fig. 10. Millipedes of the family Polydesmidae in copulation. 

 The male is below. (After Seifert, 1932.) 



The male Polydesmus angustiis approaches the female from be- 

 hind and runs along her back until her head is reached. Suddenly 

 turning round towards her ventral surface, he seizes her gnatho- 

 chilarium with his mandibles, retaining this hold until her body is 

 for the most part of its length embraced in his broader grasp. It is 

 interesting to note that a fertilised female, when touched on the 

 anal segment by a male, immediately darts forward and refuses to 

 be caught. The fertilised females in a collection can be readily 

 recognised by touching lightly on the anal segment with a camel- 

 hair brush (Evans, 1910). In Glomeris marginata the male is much 

 smaller than the female and copulation takes place by apposition 

 of the pair in the head to tail position. In contrast to the Protero- 

 spermophora, copulation in the Oniscomorpha is brief, which may 



