210 LEPIDOPTRRA. 



the manner in which it catches hold of the fore-wing, 

 as they are both expanded, can be observed. These 

 moths fly in the twihght and djjring the day. Chil- 

 dren living in the southern states can often see the 

 common ruby-throated humming-bird and this moth 

 in the twilight, both supporting themselves upon their 

 rapidly vibrating wings, while their long sucking- tubes 

 (in one a bird's beak and in the other the unrolled 

 tube of a moth) are thrust into the depths of flowers 

 on the same stem. They are not so abundant in the 

 middle and northern States, but may nevertheless be 

 observed when in motion, and when it is so dark that 

 the differences in coloration are not clearly distinguish- 

 able. The resemblance of the moth to the humming- 

 bird can then be seen to consist in its quick, darting 

 flight, and its habit of sucking the nectar of flowers 

 while supporting itself in the air. 



The larva known as the "potato-worm " (Fig. i6i, ^) 



Fig. i6i, a. 



is found on both the potato and tomato plant. It also 

 feeds upon the tobacco plant in the northern States. 

 Near the end of its body there is a single "horn" or 

 projecting spike. 



The caterpillar has the habit of raising the forward 

 part of the body, and remaining motionless in this 



