

the Growth and Habits of Carausius morosus. 369 



more or less in a straight line with the abdomen. The 

 split skin can then almost immediately be seen as it were 

 moving across the sides of the head, and at the same time 

 the apical abdominal segment can be seen to have slipped 

 down from the inside of the old and contracting integu- 

 ment, which commences to fall over backwards. There is 

 now a considerable bend at the thoracic-abdominal joint 

 as the body slowly glides down out of the skin, and the 

 antennae are forced forward by the pressure of the skin. 

 Then the middle-legs get loose and begin to spread side- 

 ways, quickly followed by the hind pair. Immediately 

 afterwards the antennae and first pair of legs get free, the 

 latter spreading out like the others and the antennae now 

 no longer holding up the head, this moves slowly backwards 

 and downwards in a line with the whole body into its 

 normal position. 



The nymph is now in the same outstretched pendant 

 attitude it assumed when the ecdysis started, except that 

 it hangs by the last two abdominal segments, kept there 

 by the contraction of the discarded exoskeleton, instead 

 of by its hind-legs, the old skin being still suspended by its 

 now empty leg skins. 



As the slough is left by the body it contracts and we have 

 thus two motions, the contracting old skin moving upwards 

 and the body moving downwards. The latter motion is 

 quite involuntary on the part of the nymph or insect, being 

 due to the action of gravity after the skin over the pro- 

 and mesonota supporting the body has split, which lets 

 the body slide down and out. 



If at the beginning of the moult the nymph falls from its 

 support it cannot get free from the old skin, and succumbs 

 in spite of its wriggling while on the ground; but if the 

 ecdysis is well advanced before such a fall the nymph will 

 generally get free. 



The time taken to get to the clearance point is about 

 20 to 45 minutes or a little more. The nymph remains 

 almost motionless in this position for about 30 or 40 minutes 

 more, when it will make a sudden convulsive movement, 

 bend its body forward, bring up its head and reverse its 

 position, now hanging by its first pair of legs, head upwards, 

 quite clear of the slough. The whole procedure, now com- 

 plete, occupies from 55 to 70 minutes from start to finish. 



In this, the final position, the nymph or insect remains 

 quiescent from a few minutes to several hours, after which 



