LARV^ AND METAMORPHOSES 33 



first place, the pupa or chrysalis is much more like the moth than the 

 puparium or skin of the blow-fly larva is like the blow-fly. In 

 the second place, the caterpillar, with its antennae, eyes and three 

 pairs of jointed, walkmg legs, is much more like an insect than is the 

 legless maggot. 



Some small msects of which the oil-beetle is a good example 

 expand the contracted history of the higher insects still more. 

 The eggs hatch out into active larvae showing a head bearing eyes 

 and antennae, a body of three joints each bearing a pair of fully 

 formed clawed legs, and a jointed abdomen with a pair of long 

 bristle-like projections behind. 

 These larvae (Fig. 17), although 

 they have no wings, are insect- 

 like in form, and are called 

 Campodeiform larvae ; no one 

 observing them for the first 

 time could doubt but that 

 they are insects of a primitive 

 kind ; moreover they are ex- 

 tremely like the members of 

 the lowest group of existing 

 insects, the Aptera or wingless 

 insects, of which the silver-fish 

 and the bristle-tail are weU- 

 known examples. These larvae 

 run about, climb up flowers, 

 and have the instinct of clinging to any hairy object. If a bee 

 comes their way, on a visit to a flower, they at once seize hold 

 of its hairy body. If it is an unsuitable bee, they perish, but 

 if it is the right kind for their purpose {Anthophora or Andrena) 

 they are carried to the nest of their host, and when the bee lays 

 an egg in a cell, the larva slips off and climbs on the egg which 

 is floating in the honey. The larva eats the contents of the egg 

 and then moults. The second larva which comes out is much less 

 like an insect than the first ; it is a fleshy grub, not well divided into 

 head, body, and abdomen, and with three short pairs of legs. It is 

 intermediate between the degenerate maggot of the blow-fly and 

 the caterpillar of the moth. This grub floats in the honey and 

 devours it and then moults once more, a stiU more degenerate motion- 

 less form appearing, with no movable appendage on the head and 

 with only six stumps in the place of the legs. This in its turn 



c.A. c 



Fig. 17. Larvae and Pupa of the Oil- 

 Beetle. Figure to the left, Campodei- 

 form larva ; middle figure, maggot- 

 like larva ; figure to right, pupa. (After 

 Packard ; much enlarged.) 



