

The Growth and Habits of Carausius morosus. 365 



different from their position in the egg), and tumble off 

 the leaf ; but generally they bend the head down, bringing 

 the mouth close to the surface of the leaf as though in search 

 of food. This search ultimately proved to be a search 

 for moisture, which when found is imbibed with avidity. 

 Occasionally the nymphs remain quietly imbibing water 

 for as long as seven minutes, at other times much less, and 

 at times only imbibing when their mouth was pushed into 

 the moisture previously placed on the leaf. 



It was in watching this imbibition that it became obvious 

 to me that within a few hours of hatching out the nymphs 

 rapidly increased their length by several millimetres per 

 day, average 2*7 mm. in 24 hours. 



Further examination showed that whether moisture was 

 imbibed or not the increase was, with few exceptions, 

 general. Of 164 newly hatched specimens put under 

 observation, of which 47 were under 10 mm. long at 

 emergence, all except 5 had increased to over 12-15 mm. 

 long, or to an average length of 133 mm. at the end of 

 24 hours. This increase was probably due to the moisture 

 taken up, for when not supplied with moisture the extension 

 was slower. It cannot be due to food partaken, for dur- 

 ing the first 24 hours hardly anything is eaten. Out of 

 206 specimens placed under observation only 56 ate at 

 all, and the amount partaken was so infinitesimal, about a 

 square millimetre or less, that it can be left out of con- 

 sideration. The swift increase in length during the first 

 24 hours is the more extraordinary when we consider the 

 results obtained in the life records of 26 specimens. From 

 the date of hatching out till the first ecdysis, i. e. during 

 an average period of 26 days, the average increase was 

 only 10*1 mm. or under "5 mm. per day. It is perhaps not 

 correct to speak of the increase during the first 24 hours 

 as a growth, but it should rather be spoken of as a physical 

 extension or stretching out of the tissues after getting 

 away from the confinement of the shell, which is largely 

 aided by any moisture imbibed. The process is in all 

 probability comparable with the universal phenomenon 

 in Crustacea to stretch immediately after moulting. 



The Growth to the First Ecdysis. 



Subsequent to the extension which takes place, as 

 already described, during the first 24 hours after hatching 

 out, the nymphs commence to feed and to grow (Table 



