THE BUTTERFLIES AND MOTHS 109 



the caterpillars are very abundant, many of them do not 

 go into the ground, but change to -pupae beneath whatever 

 shelter may be at hand. About a fortnight later, another 

 change takes place, and the fully developed moth emerges 

 from the pupa, thus completing the cycle of the insect's 

 life. The moths fly toward dusk and at night, and by 

 means of their long tongues, coiled up when not in use, 

 they suck the nectar of various flowers. 



During ordinary years the Army Worm is present in 

 most of the regions where its outbreaks occur, individual 

 caterpillars feeding in meadows and pasture lands, but the 

 number is not sufficient to attract notice. At such times, 

 their habits of life are very similar to those of the common 

 Cutworm, to which, indeed, the Army Worm is closely re- 

 lated. It is only when the caterpillars become so nu- 

 merous that they exhaust the food supply of the field in 

 which they develop, that the " army " habit is assumed. 

 Then, however, they are forced to seek new quarters for 

 food, and as their only mode of progress is by crawling 

 along the ground, they move in solid masses toward ad- 

 jacent fields. They feed preferably upon the various 

 grasses and grains, although, when driven by hunger, they 

 will eat the leaves of clover and other plants. 



One of the most effective means of preventing the in- 

 juries of these armies of caterpillars is to dig a deep ditch 

 or trench, into which the worms fall in great numbers, 

 where they can be destroyed by various mechanical devices. 



The Cutworms form one of the most vexatious groups 

 of injurious insects. They are the smooth-skinned, thick- 

 bodied worms, an inch or so in length, which are so often 

 to be found by careful digging about a tomato or cabbage 

 plant that has been cut off in the night. They attack a 

 great variety of crops and often cause serious losses. 



