366 Mr. H. Ling Koth's observations on Carausius. 



VII). This growth continues for 17 to 24 days (average 

 about 21 days), during which time it increases in length at 

 the rate of - 35 to "7 mm. per day, or a total increase of 

 3 to 5'5 mm. This is the only period of its life during which 

 it grows without shedding its outer skin, for the differences 

 in length, if any, observed during the stadia between the 

 successive ecdyses are infinitesimal. Towards the end 

 of the 21 days or so the nymph has become very rotund, 

 the abdominal segments bulge out very distinctly, it 

 ceases to feed, and consequently to excrete, and remains 

 quiescent. These are the outward evidences that ecdysis 

 is about to take place. 



The Ecdysis. 



The fasting indulged in preparatory to slipping out of 

 its old skin increases from 2 to 6 days, according to the 

 number of moults it has or has not gone through. As per 

 Table XIV, the average number of days' fast for the first 

 moult is 2'7, and for the sixth moult 4*5. 



As the moment approaches when the old skin is to be 

 discarded the nymph gets into position by suspending it- 

 self from a twig or other object by its hind-legs, allowing 

 the other two pairs to extend loosely more or less at right 

 angles to its body and the antennae equally spread out. 

 It takes 3 to 4 minutes to get into this position. Before 

 it has quite settled to this it sways its body laterally in the 

 way common to all the insects, but it ceases to do so when 

 settled, and if there is any body movement during the 

 ecdysis it somewhat resembles a faint longitudinal tremor, 

 which becomes pronounced only when the slipping out is 

 not progressing satisfactorily. There is no further lateral 

 movement nor any turning nor twisting. The preliminary 

 common lateral movement may do something towards 

 easing the skin preparatory to discarding the old skin, 

 but it is quite a distinct movement from the rare one 

 observed in the actual ecdysis. 



After hanging for a very few minutes in the position 

 indicated the nymph attaches its fore-legs to the femurs of 

 the middle-legs, or occasionally to the twig or leaf from 

 which it is suspended, if close enough. This brings the 

 head to point upwards instead of downwards and more 

 than parallel with the body, so that the head is at an acute 

 angle with the pronotum and the pronotum is at right 

 angles to the mesonotum, while the metanotum remains 



