IV. INSECT A: HEXAPODA. 



475 



ditions larvae widely remote from the systematic standpoint may 

 closely resemble each other, while those of closely related species 

 may differ extremely. The leaf -feeding larvae of Lepidoptera (fig. 



FIG. 501. 



FIG. 502. 



FIG. 503. 



FIG. 501. Pupa of Sphinx ligustri. (After Ludwig-Leunis.) i, eye; 2, head ; 3, an- 

 tennae; -6', thoracic somites; 7, hind, #, fore wing; &, legs; J0, proboscis; Ji, ab- 

 dominal somites ; J2, spiracles. 



FIG. 502. Larva of Sphinx liyustri. (After Ludwig-Leunis.) 71, caudal disc ; p, tho- 

 racic feet ; ps, prolegs. 



FIG. 503. Larva (maggot) of blowfly, Musca vomitoria. (After Leuckart.) 



502) and Tenthreds are brightly colored, the thoracic appendages 

 remaining small, and are reinforced by the fleshy ventral append- 

 ages, the prolegs or pedes spurii. The predacious larvae of many 

 beetles and Neuroptera have long thoracic legs, strong mandibles, 

 and no prolegs. Other beetle larvae, which burrow in wood or 

 live in the earth (fig. 500), have plump whitish bodies, with the 

 legs rudimentary or wholly lacking. These lead to the maggot- 

 like larvae, in which the mouth parts are inconspicuous and the 

 distinction between head and thorax may vanish. Such soft-skinned 

 annulated sacs occur in the bees (fig. 59) and other Hymenoptera, 

 as well as in many flies (fig. 503) ; that is, in animals which live 

 in an abundance of food either because of parasitism or because 

 the mother has provided plenty. 



From the outer appearance one would gain the impression that 

 these holometabolous larvae not only lacked the wings, but that the 

 appendages of the imago were entirely absent or had an entirely 

 different form; farther, that wings, and frequently antennae, legs, 

 and mouth parts, come into existence at the moment of pupation, 

 and then in remarkable size and completeness. A more accurate 

 investigation shows that the anlagen of all these structures are 

 formed long before pupation, often at the first molt. The wings 



