248 LECTURE XVllI. 



of the life of the Orthopterous insect^ from exclusion to flight, may, 

 if its organisation during that period be contrasted with that of the 

 Lepidopterous or Coleopterous insects, be called an active nymph- 

 hood. 



Entomologists, overlooking that stage of the orthopterous and 

 hemipterous insects in which they are masked by the vermiform or 

 true larval condition, have arbitrarily applied the term " larva " to 

 the more advanced stage in which these insects, with certain Neu- 

 roptera, quit the egg. Mr. Westwood, seeing that at this stage they 

 are nearly similar in form to the perfect insect, though wingless, has 

 proposed to call them " homomorphous," or "monomorphous;" and 

 those insects in which the larva is generally wormlike, &c. " hetero- 

 morphous." It needs only an acquaintance with the embryonic 

 changes of a cockroach or cricket to feel how inapplicable is the term 

 monomorphous or uniform to such an insect or its development. 



In the Coleoptera and Lepidoptera the general articulate type is 

 longer retained, and the particular one later acquired : in the He- 

 miptera and Orthoptera, the morphological and histological changes 

 more rapidly and uninterruptedly effect the ascent from the common 

 to the special form. The insects with a so called imperfect metamor- 

 phosis, contrary to the statement of Burmeister*, do pass through the 

 earlier forms of the articulate subkingdom, but more rapidly and 

 uninterruptedly than those in which the metamorphosis has been 

 deemed more complete. In these the worm-like insect or larva is 

 active, and the crab-like insect or pupa passive ; in those the larva is 

 passive and the pupa active. 



If the different stages in the development of man were not hidden 

 in the dark recesses of the womb, but were manifested, as in insects, 

 by premature birth and the enjoyment of active life, -with a limita- 

 tion of the developmental force to mere growth ; if the progress of 

 development was thus interrupted and completed at brief and remote 

 periods, with great rapidity, and during a partial suspension of active 

 life ; — his metamorphoses would be scarcely less striking and extreme, 

 as they are not less real, than those of the butterfly. 



As the insect must pass through the earlier forms of the Articulate, 



* Burmeister's statement is, " In insects with an imperfect metamorphosis there 

 cannot consequently " (the consequence is a hypothetical necessity in Nature, for a 

 difference among insects with respect to their metamorphosis) " be a passage throufh 

 the earlier forms and grades of the animal kingdom." (Shuckard's Translation, 

 p. 423. ) But no insect ever passes through the forms and grades of the radiate 

 subkingdom. Commencing as a Hydatid, it quits that subkingdom by the analogy 

 of the Entozoa, and its subsequent grades are through the forms of the Articulat'a 

 exclusively. No insect ever is or resembles the ciliated Infusory, the Polype, or the 

 Acalephe. 



