44 



Development and Metamorphosis 



gots of the flesh- and house-flies, and the helpless soft white grubs in the 

 cells of bees and wasps. These strange young, so unlike their parents, 

 have the generic name larva-, and the stage or life of the insect passed as a 

 larva is known as the larval stage. In almost all cases these larvae have 

 mouth-parts fitted for biting and chewing, while most of the adults have 

 sucking-mouth parts; the larvce have only simple eyes and small inconspicu- 



Fic. 75. — Metamorphosis, complete, of monarch butterfly, Anosia plexipptis. a, egg 

 (greatly magnified); 6, caterpillar or larva; c, chrysalid or pupa; d, adult or imago. 

 (After Jordan and Kellogg. Natural size.) 



ous antenna; the adults have both simple and compound eyes and well- 

 developed conspicuous antenna;; the larv'a; may have no legs, or one pair or 

 two or any number up to eight or ten pairs; the adults have always three 

 pairs; the larvas are wholly wingless, nor do external wing-pads (i.e., 

 developing wings) appear outside the body during the larval stage; the 

 adults have usually two pairs (sometimes one or none) of fully developed 

 wings. Internally the differences are also great. The musculation of the 



