MORPHOLOGICAL ADAPTATION IN INSECTS — GRANDI 223 



portions of organs, each of which has, of course, its own function 

 related to the functions of others, within the hmits of the general 

 behavior, 



5. The modifications undergone by a group of organs in connection 

 with a particular function often affect different organs of the same 

 complex or different portions of the same organ in different species, 

 genera, families, and orders. 



6. The modifications affecting the same organ may be different (but 

 all coordinated with the same function) and more or less advanced 

 in a determinated sense in the various species of a genus (or a higher 

 taxonomic group). 



7. The modifications of organs or somatic regions may concern 

 only one half of them (antimeric) and so determine an asymmetric 

 structure. 



8. An organ so modified as to acquire an inpractical form and size — 

 that is, a hypertelic organ — may exhibit other corrective modifications 

 which seem to attenuate the functional inconveniences caused by its 

 abnormal structure. 



9. An organ that has disappeared during a phase of the postem- 

 bryonic development may appear again in a second phase of the same 

 development and therefore of the ontogeny. 



10. An organ that has disappeared during postembryonic stages of 

 a whole family, evolving in a particular environment, may be found 

 in the postembryonic stages of some representatives of the same 

 family living (probably owing to a secondary adaptation) in a dif- 

 ferent environment. 



11. The modifications undergone by the organisms studied by me, 

 which as stated before are always connected with the function the 

 organs have to perform, generally do not seem to be necessary, often 

 not even useful,'^ sometimes even a hindrance (if not disgenic). 



12. In fact, species belonging to the same taxonomic group (for in- 

 stance to the same family) may live and develop in environments like 

 those inhabited by the modified forms, and perform basically similar 

 functions, but conversely may have undergone no modifications. 



13. It even happens that in a hypermetamorphic species two types 

 of larvae, the first highly modified, the second quite unmodified 

 (which, however, bore diversely shaped mines and feed in a different 

 way) follow each other in succession during the postembryonic de- 

 velopment and in the same microhabitat. 



14. There are species (hypermetamorphic and parasitic) that have 



■^ As far as known at present. 



