102 FOOD OF INSECTS. 



the destructive enemies of other productions of nature, and objects of perse- 

 cution to farmers, gardeners, and foresters. 



313. The nympha or pupa state succeeds that of larva. In this state 

 insects for the most part take no nourishment (with the exception of the 

 Orthopterous, Hemipterous, and part of the Neuropterous species, which vary 

 but little in form from the larva), and repose in a death-like slumber. The 

 body is covered with a skin more or less transparent, through which the 

 limbs of the perfect insect are more or less apparent. To be safe from 

 their enemies, or from the weather, the larvae of many insects, particularly 

 moths, prepare for themselves a covering of a silky or cottony texture; 

 many burrow in the soil, or form themselves a nest of moss, leaves, grass, 

 haulm, or foliage ; many even go deep into the earth, or bury themselves 

 in decayed wood, or conceal themselves under the bark of trees, &c. 



314. After a certain period, which is fixed in every species of insects, and 

 which can either be hastened or retarded according to circumstances, the per- 

 fect insect appears from the pupa. It is usually furnished in this state with 

 other organs for the performance of its appointed functions. It is incumbent 

 on the perfect insect to propagate its species, therefore the organs for this 

 purpose are only perfected at this period of their lives. The male insect 

 seeks the female, and the female the most suitable place for laying her eggs; 

 hence most insects are furnished with wings. Food is now a secondary 

 consideration, consequently, in many, the feeding organs are now less perfectly 

 developed than in the larva state, or very much modified and suited for finer 

 food, as for example in butterflies, which, instead of the leaves of plants, 

 only consume the honey out of their flowers. 



Subsect. 3. Food of Insects. 



315. Insects, like other animals, derive their nourishment from the vege- 

 table and animal kingdoms ; but a glance is sufficient to show, that they 

 possess a much wider field of operations than the others. While the other 

 animals make use for their subsistence of only a small portion of the inex- 

 haustible treasures of the vegetable kingdom, and reject the rest as insipid 

 or noxious, the insects leave perhaps no vegetable production untouched. 

 From the majestic oak to the invisible fungus, or the insignificant wall-moss, 

 the whole race of plants is a stupendous meal, to which the insects sit down 

 as guests. Even those plants which are highly poisonous and nauseating to 

 other animals are not refused by them. But this is not yet all. The larger 

 plant- consuming animals are usually limited to leaves, seed, and stalks : not 

 so bisects, to the various families of which every part of a plant yields suit- 

 able provender. Some which live under the earth attack roots, others 

 choose the stem and branches, a third division live on the leaves, a fourth 

 prefers the flowers, while a fifth selects the fruit or seed. 



316. Even here a still further selection takes place. Of those which feed 

 on the roots, stem, and branches, some species only eat the rind, like the 

 bee-hawk-moth (Sphinx apiformis) ; others the inner bark and the albur- 

 num, like the Tortrix Wcebermna, and the injurious bark-beetle ; and a 

 third division penetrates into the heart of the solid wood, like the 

 goat- moth (Cossus ligniperda), and the family of the long-horned beetles 

 ( Cerambycidae). 



317. Of those which prefer foliage, some take nothing but the juice out of 

 the veins (aphides, in all their states) ; others devour only the substance of 



