METAMORPHOSIS 



159 



Insects that have complete metamorphoses, and are not 

 supplied with food by their parents or guardians, are provided 

 during their larval life with special modifications of extremely 

 various kinds to fit them for the period of life during which they 

 are obtaining food and growing. Thus caterpillars possess numer- 

 ous adaptations to fit them for the period during which they 

 live on leaves, while maggots have modifications enabling them to 

 live amongst decomposing flesh. Some larvae are greatly modified 

 in this adaptive way, and when the adaptations change greatly 

 during the life of the larva, hypermetamorphosis is said to exist. 

 As an instance we may mention some beetle larvae that are born 

 with legs by whose aid they can cling to a bee, and so get 



Fig. 86. — Prepara- 

 tory stages of 

 Sitaris humer- 

 alis: 9, 10, 11, 



12, first, second, 

 third, and fourth 

 larval instars ; 



13, pupa. (After 

 Lnbboclc and 

 Fabre.) 



carried to its nest, where they will in future live on the stores 

 of food the bee provides for its own young. In order that they 

 may be accommodated to their totally different second circum- 

 stances, they change their first form, losing their legs, and be- 

 coming almost bladder-like creatures,, fitted for floating on the 

 honey without being injured by it. Such an occurrence has 

 been described by Fabre ^ in the case of Sitaris humeralis, and 

 his fio-iu-es have been reproduced in Sir John Lubbock's book on 

 the metamorphoses of Insects,^ as well as in other works, yet they 

 are of so much interest that we give them again, especially as the 

 subject is still only in its infancy ; we at present see no sufficient 

 reason for the later of these larval states. Little is, we believe, 

 known as to the internal anatomy of the various instars in these 

 curious cases. 



1 Ann. Sci. Nat. Zool. Ser. iv. vol. vii. 1857, pi. 17. ^ Nature Series, 1874. 



