INSECTS 13 



12. Distinguishing characteristics of moths. The moths and 

 butterflies belong to the same order of insects; that is, the scaly 

 winged insects. But there are some characteristics in which these 

 two kinds of insects differ. For instance, moths when at rest fold 

 the wings horizontally (Fig. 11), while butterflies fold them verti- 

 cally, that is, erect (Fig. 10). The wings, too, of moths are not 

 usually as brilliantly colored. Most moths fly at night, while 

 butterflies are day-flyers. The body of moths is usually relatively 

 broader than that of butterflies. Moth antennae are of various 

 shapes, often like a feather, but never knobbed. 



In general, the life history of moths is very much the same as 

 that of butterflies, but the larvae of many moths spin a more or less 

 silky mass of threads about themselves, as is the case with the silk- 

 worm caterpillar (Fig. 16), and this outside covering of the pupa 

 stage is known as the cocoon. 



13. Economic importance of butterflies and moths. 

 The larvae of both butterflies and moths are voracious 

 feeders, as any one knows who has had any experience with 

 caterpillars. In fact, they may be called animated feeding 

 machines, since the animal must not only provide for its own 

 growth, but must also store up enough food to form the new 

 parts such as the wings and the legs. Not all larvae of butter- 

 flies and moths are considered harmful, however, since 

 some of them are not prolific enough to have any serious 

 effect upon vegetation, which is the source of food of most 

 caterpillars. This is true of many of the butterfly larvae 

 and of some moth larvae. Then, too, some of the larvae 

 feed on plants that are not useful to man. This is true of 

 the larva of the monarch butterfly (Fig. 6), which feeds upon 

 leaves of the milkweed. The adult butterflies and moths 

 of course are not capable of doing any harm since, when they 

 eat anything at all, they most commonly suck the nectar 

 of flowers. When the flowers are visited in this way, 



