INSECT METAMORPHOSIS 



to have some kind of protection, either from the weather, 

 or from predacious creatures that might destroy it. While 

 most pupae are protected in one way or another, there are 

 some that remain in exposed situations with no kind of 

 shelter or concealment. The mosquito pupa is one of 

 these, for it lives in the water along with the larva and 

 floats just beneath the surface (Fig. 174 F), breathing 

 by a pair of trumpetlike tubes that project above the 

 surface from the anterior part of the body. The mos- 

 quito pupa is a very active creature, and can propel itself 

 through the water, usually downward, with almost as 

 much agility as can the larva, and by this means probably 

 avoids its enemies. The pupa of the common lady-beetle 

 gives another example of an unprotected pupa (Fig. 

 132 E). The larvae of these insects transform on the 

 leaves where they have been feeding, and the pupae re- 

 main here attached to the leaf, unable to move except by 

 bending the body up and down. The pupae of some of 

 the butterflies also hang naked from the stems or leaves 

 of plants. 



The pupae of many different kinds of insects are to be 

 found in the ground, beneath stones, under the bark of 

 trees, or in tunnels of the leaves, twigs, or wood of plants 

 where the larvae have spent their lives. Some of these, 

 especially beetle pupae, are naked, soft-bodied creatures, 

 depending on their concealment for protection. The 

 pupae of moths and butterflies, however, are character- 

 istically smooth, hard-shelled objects with the outlines 

 of the legs and wings apparently sculptured on the sur- 

 face (Plate 14 F). Pupae of this kind are called chrysa- 

 lides (singular, chrysalis). Their dense covering is formed 

 of a gluelike substance, exuded from the skin, that dries 

 and forms a hard coating over the entire outer surface, 

 binding the antennae, legs, and wings close to the body. 

 In addition, the pupae of many moths are inclosed in a 

 silk cocoon spun by the caterpillar. The caterpillars, 

 as we shall learn in the next chapter, are provided with 



[251] 



