the Growth and Habits of Carausius morosus. 385 



male was found and there is a possibility of its being de- 

 generated ; it had no contact with any of the females under 

 observation . 



The length over all of the egg capsules varied from 2' 3 

 to 3" 2 mm., average 2*8 mm. Under 2*6 mm. long they 

 did not hatch out. The fertility of the eggs was found to 

 be 81'5%. 



Eggs are first dropped 12 to 24 days (average 16 '5 

 days) after the last ecdysis ; they are neither laid nor shot 

 out, but simply dropped. 



The average egg production was found to be 513 per 

 insect, the highest total reached by one insect being 712. 

 There appeared to be no correlation between the size 

 (length of the insect) and the quantity of eggs produced. 



The nymphs emerged by pushing off the cap of the egg 

 and appeared to come out pronotum first, and not head 

 first. The length of the nymphs on hatching out varied 

 from 7*5 to 12*5 mm., average 10 "5 mm. Almost in- 

 variably on hatching out they were eager for a drink, but 

 not keen to eat. At the end of 24 hours their average 

 length was 13 '3 mm. From the time of hatching out the 

 nymphs grew at the rate of "35 to *7 mm. per day, for an 

 average of 21 days, with a total increase of 3 to 5*5 mm. 

 This is the only period during which the nymphs grow 

 without shedding the skin. 



The nymphs fast from 2 to 6 days pevious to the actual 

 moulting. The ecdyses were performed by the nymph 

 hanging head downwards, the skin splitting from the 

 pronotum upwards, when gravity did the rest. There 

 were in all the cases observed six ecdyses for each insect. 

 The increase in length at every ecdysis was so marked that 

 it was possible to ascertain by measurement the stadium 

 in which the nymph or insect might happen to be. 



The length of the full-grown insects varied from 72 to 

 86 mm. (exclusive of the antennae), average 80*1 mm., 

 equal to a range of 14 mm. The progeny from eggs dropped 

 late in life attained to a greater length than that from eggs 

 dropped early in life.* The body length increased six- 

 fold ; the antennae increased in the same total ratio ; but 

 the increase in the various segments was more and less. 



With the exceptions named the nymphs and insects 



* It is noteworthy that Elkind states that in D. morosus the 

 eggs are smaller during the earlier stages of production than later 

 on {op. tit., p. 14). 



