GENERATION OF INSECTS. 437 



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

 morphous or uniform to such an insect or its development. 



The chief business of an insect, for good or for evil, is performed 

 in its larval state. The moth, which destroys our clothes, does it 

 not in its complete, but its larval, stage. The cockchafer, which 

 makes the young wheat-blade wither and fall, is a mere grub- Me- 

 tropolitan duties shut out much of the field of nature ; but still she 

 may be found and studied everywhere. I first learned to appreciate 

 the true nature and relations of the nominally various and distinct 

 metamorphoses of insects, by watching and pondering over the de- 

 velopment of a cockroach, which quits the egg as a crustacean. I 

 saw that it passed through stages answering to those at which 

 other insects were arrested : there was a period when its jointed 

 legs were simple, short, unarticulated buds, — when its thirteen seg- 

 ments were distinct and equal, — when it was apodal, — when it was 

 acephalous. 



Now, the differences of the larvae which are distinguished by the 

 entomological terms, Heteromorphous, Homomorphous, Capitate, &c., 

 essentially depend upon their quitting the egg to enter into active 

 life at different periods of development, arrested at different grades. 

 And it is most interesting to observe, that these several grades are 

 analogous to, or are typified by, the complete forms of the different 

 recognised classes of the great articulate sub-kingdom. 



These phenomena of insect-development are most important in 

 zoological classification. They establish satisfactorily our ideas of the 

 natural character of a true natural group, as also the natural progres- 

 sion of the affinities of its several grades. 



When we see the entozoiform acephalous type assumed by an insect 

 in the first transformations of the germ-mass, we feel an assurance 

 nothing else could give, that we are in accordance with Nature in 

 commencing the ascending series of articulate animals, which are 

 to culminate in the winged insect, from the entozoa. 



When we find that the annulose w^orm, with a modified segment 

 for a head, and tubular feet, is the next form assumed, according to 

 the type of the anellides, we are thereby confirmed in our departure, 

 in this instance, from the authority of the great Cuvier, who, through 

 assigning undue value to a single character, the colour of the blood, 

 placed the anellides at the head, instead of near the foot, of the 

 articulate series. 



When the next step is seen to be the acquisition of articulate 

 limbs and jointed antennee, we conclude that the articulated animals 

 arrested at this grade of outward form ought to be the next in posi- 

 tion in the series, notwithstanding that certain higher members of 



