ORDER IV.— MOTHS AND BUTTERFLIES. 185 



tend to the hind part of the body, and thence back to the 

 neck, where they open at the inferior lip. Those tubes con- 

 tain the substance which the animal uses in spinning, which 

 is a yellow or white juice, according to the food it takes, 

 and upon this also probably depends the fineness of the silk 

 they make, in the same manner as the quality and color of 

 butter depends upon the food of the cow. 



These tubes joining together and opening at the under 

 lip, constitute the spinning apparatus of caterpillars, and 

 may be distinctly seen by opening with great care and cau- 

 tion the back of the animal. The juice contained in the 

 tubes is nothing more nor less than a kind of very fine var- 

 nish, of which the people of some countries make use, but 

 which no one has yet undertaken to use in this country. 

 Should this varnish ever come into general use, our most 

 noxious caterpillars would become beneficial to us. 



Figure 27. 



Saturnia lo. — Male, 



The single parts of Moths and Butterflies, although not 

 quite as varied and complex as those of caterpillars, still 

 present some points of interest and curiosity, and far excel 

 them in beauty and splendor. 



The four wings of Moths and Butterflies differ from those 

 of other insects, by being covered with a kind of dust, which 

 produces the handsome colors, and which, when touched, 

 sticks to the fingers. Under the microscope, it is seen that 



