96 SECOND REPORT OF THE STATE ENTOMOLOGIST. 



cial purposes. It consisted only of a few loose silken threads for support 

 and a thin sheet for covering, thrown across and within the upturned 

 edges of a leaf of their food-plant. Through this thin webbing the 

 caterpillar could be seen for two days after the spinning, when, by 

 gradual contraction and finally throwing off the caterpillar skin, it 

 assumed the pupal form. The pupa could be watched day by day grow- 

 ing darker in color as the insect within was taking form and substance, 

 until twenty days had passed, when the beautiful moths, one after 

 another, emerged. 



Beauty of the Plusia Moths. 



Guenee, in his Histoire Naturelles cles Insectes, thus discourses upon 

 the beauty of these moths : 



The perfect insects are, without exception, most beautiful. Some of 

 them claim our admiration from their satiny plates in bronze or reddish- 

 brown, of which the most conspicuous precedes the terminal border, and 

 reaches, in gradual contraction, the median space behind the basilar line. 

 But the larger number, in addition to these plates which occur with 

 almost all, bear a particular ornament. This ornament consists in one 

 or two spots placed beneath the cell, peculiar to this genus and not answer- 

 ing to any of the three ordinary spots. These spots are colored with a 

 matter which imitates polished gold or silver in color and brilliancy. 

 They are slightly raised upon their borders as if some drops of these 

 rich colors had fallen upon the wing and become depressed in the mid- 

 dle in drying. But, like all the rest of the wing, they are composed of 

 imbricated scales, of which the exterior ones form a hem in rounded out- 

 line, instead of being transversely disposed as are all the other scales of 

 the wing, even those which form the metallic portions often as brilliant 

 as are these particular spots. 



But it is not only by their brilliancy that these spots are remarkable ; 

 it is also by their form, which is not less essential, and which serves us 

 potently in distinguishing the species. Sometimes they are but simple 

 rounded plates, sometimes two contiguous points ; more frequently the 

 posterior one has the form of an oval point, while the anterior is shaped 

 like a hook more or less open, resembling a U or a Y, or yet an interro- 

 gation point wanting its dot beneath. Finally, the two spots are bound 

 together, and then the posterior sign takes the form of a tear or a drop> 

 and the entire figure represents a gamma or a lambda reversed. Both 

 of these and other names of letters and characters have been called in 

 requisition for designating the species of the genus Plusia, although 

 these alphabetic signs are not always very striking. {Nodiiehfes, ii 

 p. 325-6.) 



