134 CRABS AND INSECTS. 



Butterflies (Papiliomdte). General Characteristics.-* 

 The butterflies are day-flying Lepidoptera, and distin- 

 guished from the moths by their knobbed antennae. 



Vanessa. In this genus (Fig. 169) the wings are richly 

 marked. The larva is cylindrical, and covered with stout, 

 long-branching spines. The V. antiopa is one of the com- 

 monest forms, and famous for its habits of hibernation. 



FIG. 169. Metamorphosis of the peacock butterfly ( Vanesra /<?). 



Sulphur- Butterflies (Colias)* In this family the 

 wings are rounded, and form a gutter for the reception of 

 the abdomen. They are the commonest butterflies we have. 



* In some countries they flock upon certain trees, completely 

 covering them, so that in the sun they appear to have a golden hue. 

 Darwin met a vast cloud of them, ten miles at sea, off the Bay of San 

 Bias, and as far as could be seen the swarm extended. Sir Emerson 

 Tcnnent observed a flock in India that was several days in passing a 

 given point at a high rate of speed. Sir Robert Schomburgh observed 

 a cloud of another genus crossing the Essequibo River, South America, 

 that was nine miles wide, and was nine hours in passing the stream. 



