OTHER 'MYRIAPODS' 67 



observed to seize a Symphylid with its jaws and carry it rapidly 

 away: various gregarines have been found in Scutigerella immacu- 

 lata, Hanseniella hova and H. agilis and there is a single record of a 

 nematode in the first named species (Remy, 1950). 



Many Symphyla lay a clump of eggs in a crevice or hollow of 

 the soil, attaching them to its wall by a short stalk so that the eggs 

 are free from contact with the sides or floor of the shelter thereby 

 obtaining some protection from fungi and other enemies. In Scuti- 

 gerella immaculata, 4—25 eggs are laid (Filinger, 1931): in Han- 

 seniella agilis 3-8. The young hatch with six or seven pairs of legs 

 after an average period of about eleven days: there are five further 

 stages each having one more pair of legs than the last, up to the 

 number of eleven. From this eleven-legged larva, the adult emerges 

 after a final moult. According to Fihnger (1931) the first moult 

 occurs within one to four days, usually after 24-36 hours, the 

 succeeding ones at intervals of about eight days. Sexual maturity 

 is reached after 40-60 days. During moulting a split occurs be- 

 tween the head and the first body segment, but as the whole 

 cuticle is soft it is not usually cast in one piece as in most other 

 myriapods, but is moulted irregularly in strips and tattered frag- 

 ments at various points of the body. 



Michelbacher (1938) found that S. immaculata moults from 

 time to time during its entire life, and since it may live for a 

 period of four years or more, the maximum number of moults 

 probably exceeds fifty. The moulting characteristics of different 

 individuals vary greatly: a sex factor is present and some evidence 

 has been obtained which indicates that a genetic factor may also 

 be involved. Other factors which influence moulting are: type of 

 food, temperature, humidity and mutilation. Above and below 

 28° C the moulting rate decreases. The earliest that egg-laying was 

 observed to begin was between the seventh and eighth moults 

 which would indicate that this is about the time of sexual maturity. 



In most cases however eggs are not produced until a much later 

 date. Oviposition occurs a short time before moulting. At birth, 

 the species of Scutigerella so far investigated have been found to 

 have six pairs of legs and six antennal segments, whereas Han- 

 seniella spp. have seven pairs of legs and six antennal segments 

 (Tiegs, 1945). It is surprising to find these differences in so homo- 



