246 INSECTS INJURIOUS TO VEGETATION. 



Smerintlii are heavy and sluggish in their motions. They fly 

 only during the night, and apparently, in the winged state, take 

 no food; for their tongues are very short, and indeed almost 

 invisible. The Glaucopidians, or Sphinges with feathered an- 

 tennae, fly mostly by day, and alight to take their food, like 

 many moths, which some of them resemble in form, and in 

 their transformations. The caterpillars of the Sphinges have 

 sixteen legs, placed in pairs beneath the first, second, third, 

 sixth, seventh, eighth, ninth, and last segments of the body; 

 all of them, except the yEgerians and Glaucopidians, have 

 either a kind of horn or a tubercle on the top of the last seg- 

 ment, and, when at rest, sit with the fore part of the body- 

 elevated. 



Having devoted a large portion of this treatise to a descrip- 

 tion of the spinning moths, my observations on the other 

 insects of this order must be brief, and confined to a few spe- 

 cies, which are more particularly obnoxious on account of 

 their devastations in the caterpillar state. Those persons who 

 are curious to know more about the Sphinges than can be 

 included in this essay, are referred to my descriptive catalogue 

 of these insects, contained in the thirty-sixth volume of Pro- 

 fessor Silliman's "Journal of Science." 



Every farmer's boy knows the potato-worm, as it is com- 

 monly called ; a large green caterpillar, with a kind of thorn 

 upon the tail, and oblique whitish stripes on the sides of the 

 body. This insect, which devours the leaves of the potato, 

 often to the great injury of the plant, grows to the thickness 

 of the fore-finger, and the length of three inches or more. It 

 attains its full size from the middle of August to the first of 

 September, then crawls down the stem of the plant and buries 

 itself in the ground. Here, in a few days, it throws off its 

 caterpillar-skin, and becomes a chrysalis, of a bright brown 

 color, with a long and slender tongue-case, bent over from the 

 head, so as to touch the breast only at the end, and somewhat 

 resembling the handle of a pitcher. It remains in the ground 

 through the winter, below the reach of frost, and in the fol- 

 lowing summer the chrysalis-skin bursts open, a large moth 

 crawls out of it, comes to the surface of the ground, and 



