Stick-Insects. 



131 



m 



and emerges, but as a rule it lias some difficulty in getting rid of the capsule, the 

 hooks of one or both of the hind-legs catching probably in the egg-skin. Now the 

 egg-capsule measures 3 mm. in length, and the newly emerged stick is 10 mm. in 

 the length of its body, not taking the long antennae and legs into account. Of course, 

 the discrepancy in size between the capsule and the young is explained by the fact 

 that considerable expansion has taken 

 place during actual emergence. 

 Before emergence, for example, the 

 three pairs of legs are fairly close 

 together, but during the struggle to 

 free itself from its prison the two 

 hind - joints of the middle - bodx' 

 lengthen and separate the legs con- 

 siderablv. The young stick grows 

 rapidly, and casts its skin scwral 

 times before arriving at full size and 

 egg-laying caj^acity. But in the 

 species described there are no ex- 

 ternal marks to indicate the larval, 

 nymphal, and mature stages : size 

 is our onh' guide. 



It is worth remarking that these 

 Insects resemble crabs and lobsters 

 in one respect — that is in the restora- 

 tion of lost limbs. It sometimes 

 happens that in moulting there is a 

 difficult\- in getting one of the limbs 

 free from the old skin, and in the 

 effort to do this the limb breaks off. 

 We have sometimes suspected, too, 

 that occasionally one individual dis- 

 plays cannibalistic tendencies and 

 bites off ])art of the limb of a sister. 

 However, if the loss has occ-uncd 

 during the early part of the cripj)le'> 

 life the defect \\ill be put riglii ])efore 

 the stick dies of old age. At the next 

 change of skin a new limb will make 

 its appearance on a reduced scale, 

 and at the following moult it \\ill be 

 less out of projjortuju to its ft'llows. 

 But if the accident happens later in lifi' there arc not suftic-ient moults to enable 

 the process to be completed. To an inactive creature like a stick the deprivation 

 of a limb or two does not matter greatly : it appears to get along comfortably 

 with four or five. 



A Winged Stick-Insect. 



The palophiis, which is a iiativt- of West .Africa, is one of the larg.st of the 

 stick-liisccts, nu-asuring about a foot in llu- length of the body. The 

 extension of the fore-limbs in front, as usually carried, adds another half- 

 foot to the apparent length. This is a good example also of those 

 "sticks" in wliich the wings are fully developed. The wing-covers, as 

 will be seen, are verv small. 



