l3 NliW VOKK STATE MLSELJi 



it IS easy to see how these let^less, de^jraded forms could have been derivea 

 from the more common txpe tliroii^jh a reduction of their various ors^ans. 



The hirval stage is fretjuently of prime importance to the economic 

 entomologist because it is while in this form that many insects commit their 

 greatest depredations. The young of our sawtlics may be recognized by 

 their usually cylindric form and by their having 1 8 to 22 legs including the 

 6 true or thoracic legs, while caterpillars or larvae of butterflies and moths 

 are usually provided with froni 8 to 16. The young of the more highly 

 developed bees and Hies, as previously stated, are footless, maggot-like 

 creatures and the young of most beetles possess the 6 thoracic legs and are 

 often provided with a fleshy appendage at the posterior extremity, though 

 in some, such as snout beetles and many wootl borers, all the usual 

 locomotive appendages are wanting. 



The larval stage of insects, likt- the others, may be met with under 

 \cry diverse conditions and in all seasons of the year, though its dura- 

 lion in each species is usually somewhat closely limited. The caterpillar 

 I pi. 7, fig. i| sheds its skin when full grown and changes to a pupa, a 

 stage which is frecpiently svibconical and often of a brownish incon- 

 spicuous color. 



Pupa. The assuminion of this stage is usually preceded by the larva 

 betaking itself to some sheltered place where a protective cocoon or cell 

 may be prepared. The cocoon may be very delicate and netlike as in the 

 clover leaf weevil, P h y t o n o m u s p u n c t a t u s P'abr. or with an outer net 

 and inner close woven cocoon as in Climacia or a more or less homo- 

 geneous silken covering as in the common silkworm. .Some native species 

 incorporate leaves or jjortions of ihcni in their cocoons like the- promelhea 

 moth. The larvae of many moths construct very perfect earthern cells m 

 which to undergo their final transformations while others depend on the 

 partial shelter of a crevice or curh-d U-af. Many butlertlit-s undergo trans- 

 formations in exposed situations and their chrysalids present some interest- 

 ing adaptations to surrounding objects. The angular protectively colored 

 chrysalis of the spiny elm caterpillar [pi. 10, fig. 10] is an exceedingly 



