142 



ENTOMOLOGY. 



a pair of blades. Now the tongue or proboscis of the 

 butterfly is formed by the union of these two blade-like 

 maxillse; and they are so closely united together as to form 

 a hollow tube or proboscis (c), through which the nectar is 



Fig. 171— Fore and hind wings of a butterfly, showing the venation, a, costal 

 vein; 6, subcostal; b 1 , b 2 . b 3 , b*, ft 6 , the five subcostal veinlets; c, the inde- 

 pendent vein (it is sometimes a branch of the subcostal and sometimes of the 

 median vein); d, median vein; d 1 , rt 2 , d 3 , d 4 , the four median veinlets; e, sub- 

 median vein; /, internal vein; h, iuterno-median veinlet. rarely found'; b and 

 d are situated in the " discal cell." Lettering the same in both wings.' 



sucked with the aid of the pharyngeal sac, which serves as 

 a pumping organ to suck the liquid food through the pro- 

 boscis, and force it backwards into the digestive canal. 



The wings of butterflies are beautifully painted and or- 

 namented. If, however, we examine the scales separately 

 under the microscope, we shall see that they are colorless. 

 The variety of color on the different spots and bands is 

 due to the arrangement of the scales, i.e., to the interfer- 

 ence of the rays of light passing through them. 



In the butterfly, as in the house-fly, it will be seen that 

 the front edge of the fore wings is strengthened by two 



