18 ON TIIR TRANSFORMATION OF INSECTS. 



In turning to the other section of the Amorpha, the Amor- 

 pha Adermata, the butterflies, moths, and gnats, we find, 

 on examining them in the quiescent state, abundant evidence 

 that we have before us not only organized but animated 

 beings ; in these, the grubs, before becoming quiescent, cast 

 their covering in the same manner as the bee ; but still unlike 

 that insect, retain two distinct coverings, thus resembling the 

 Amorpha Dermaia. Both these coverings are cast at the 

 same time ; the interior, fine, semi-transparent, and delicately 

 soft, must have been observed by all who have paid any atten- 

 tion to the rearing oi Lepidoptera. Now the whole of the 

 Necromorpha, as far as has yet been ascertained, finally 

 undergo a single, and the whole of the Amorpha, on the other 

 hand, a double ecdysis. 



The Isomorpha, of which the common cricket is an excellent 

 example, have no quiescent state; neither can we find that 

 they possess any state precisely equivalent to that portion of 

 the lives of the two great groups which we have been com- 

 paring. Their whole existence between the egg and the 

 imago, consists of a gradual series of approaches to perfection, 

 and during this interval, copulation certainly, and not impro- 

 bably reproduction, often takes place. No character is yet 

 known by which the penultimate, antepenultimate, and prior 

 states can be determined. 



In the heterogeneous group, Anisomorpha, a group in 

 metamorphosis, as in all other characters, equally related to 

 the other three, we find a typical and distinct section in the 

 dragon-flies {Libellnla, Lin.) These, like the Isomorpha, 

 have no quiescent state : their preparatory state is aquatic, 

 active and voracious : when arrived at the period for assuming 

 the imago, they leave the water, and fixing their feet firmly to a 

 slender stick or blade of grass, emerge from a double skin, and 

 fly away. The exterior skin is hard, corneous, and brittle ; the 

 interior, soft, fine, and pliable. Even the magnificent wings 

 leave behind them a covering, which, unfolded with great care, 

 will be found to retain an impression of their complicated 

 meshes. The May-fly {Ephemera), one of the Anisomorphous 

 insects, has a metamorphosis still more striking, and one that 

 has been deemed anomalous and unaccountable. In the ante- 

 penultimate skin it leaves the water, and attaches itself by the 

 legs like the dragon-fly. Its antepenultimate skin then opens 



