INSECTS 



9 



Egg on lower sur- 

 face of milkweed 

 leaf. 



Egg highly 

 magnified. 



7. General characteristics of butterflies. — All butter- 

 flies, as we shall see later, are constructed on much the same 

 general plan as that of other insects; i.e. their bodies are 



divided into three re- . __^ 



gions, head, thorax, 

 and abdomen; on the 

 head are two antennae 

 and a pair of large 

 eyes ; on the thorax are 

 two pairs of wings and 

 three pairs of jointed 

 legs ; and the abdomen 

 is composed of a num- 

 ber of parts called rings 

 or segments (Fig. 6). 



Egg stage. 



Larva stage (caterpillar). 



Development of pupa stage. 



8. Wings and their 

 scales. — While this 

 general plan of struc- 

 ture is common to all 

 insects, there are cer- 

 tain marked peculiar- 

 ities that enable one 

 readily to recognize a 

 butterfly. 



For instance, al- 

 though other insects 

 have two pairs of wings, 

 no others have these 

 organs so beautifully colored and relatively large. This color 

 of the wings is due (we proved in 6, C. 5) to tiny bodies 

 called scales. If the wing of a butterfly is rubbed, the color 

 comes off and the wing at that point loses its color. To 



Fig. 6.- 



Adult Stage. 



-Life history of monarch butter- 

 fly. (Weed.) 



