50 



GENERAL ZOOLOGY 



three different forms, called the early spring, the late spring, 

 and the summer form. Both of the spring forms appear from 

 pupae which have lived through the winter. From the eggs 

 which the spring forms lay the summer form develops several 

 successive broods the same year. 



Skippers. The skippers (Epargy'rem tit'yrus, Fig. 31) are, 

 like the butterflies, diurnal insects, and are found in fields 



and along 

 woods ides, 

 where they 

 dart about 



in a most erratic manner. They are 

 closely allied to the butterflies, but 

 differ from them in several details 

 of structure and habits. The butter- 

 flies (see Fig. 30) have club-shaped 

 antennae, while in the skippers the 

 antennae, though enlarged at the 

 end, are generally recurved, forming 

 a hook. The skippers have stouter 

 bodies than the butterflies, and most 

 of them hold the wings upright after 

 the fashion of the butterflies ; but 

 some hold only the anterior wings in this position. The larvse 

 of those species found in the United States can easily be dis- 

 tinguished from other caterpillars by the very large head and 

 strongly constricted neck (Fig. 31). They usually live in a 

 folded leaf, or in a nest of leaves, and pass the pupal stage in a 

 thin cocoon of silk spun by the caterpillars before changing. In 

 this latter respect, too, the skippers differ from the butterflies, 

 since the latter (as shown in Fig. 29) have a naked pupal stage. 



FIG. 31. Metamorphosis of 

 Skipper. Natural size 



