REPORT OF THE STATE ENTOMOLOGIST l6l 



The Mines. 



The larva on hatching eats into the upper surface of the leaf, leaving a 

 small white spot and slender white line as the commencement of its mine. 

 This gradually widens and curves in a trumpet shape, or like that of a 

 mussel, and at this stage is crossed with a series of gradually enlarging 

 white crescents, contrasting with the brown of the interspaces. Later in 

 the season, as shown in the leaves collected on September 2 2d, the mine 

 becomes enlarged into a broad patch, inclosing the crescent-marked 

 trumpet-form and almost obliterating it, yet by careful examination it can 

 always be found. The thin and wrinkled epidermis of the leaf which 

 covers the mine becomes of a dull reddish color, and at times, when the 

 mines are numerous, almost the entire upper surface has assumed this 

 peculiar brick-red color. The mines do not show on the under side of 

 the leaf, but when held to the light and viewed from above they are read- 

 ily seen. 



Its Life-History. 



It is not known definitely when the eggs of the moth are deposited, but 

 as it has been seen abroad in May, it is presumably toward the latter part 

 of that month or in early June. The egg seems not to have been ob- 

 served. The growth of the larva is slow, for, when observed toward the 

 last of September, it was immature and still feeding. It probably feeds 

 until prevented late in the season by the drying of the leaf. According 

 to Clemens, the larva is remarkably cleanly in its habits, and instead of 

 allowing its " frass " to accumulate within its mine, it ejects the pellets 

 through small round holes in the under surface of the leaf. It hibernates 

 within the leaf in its larval stage. Preparatory to pupation, it densely 

 lines the upper and lower surfaces of the mine with silvery white silk. " In 

 the spring it transforms to a pupa at one end of the mine, making no 

 cocoon, and in a short time forces its way partly out through the upper 

 surface of the mine and there gives forth the moth " (Brunn). A single 

 example of the pupa has been seen, and its description given by Mr. 

 C. M. Weed, loc. cit. Mr. Brunn has published a detailed description of 

 the larva. 



Its Injuries Seldom Serious. 



We do not hear of any particular harm from this insect. Even when 

 the foliage shows so severe an attack as in the leaves received, it occurs 

 so late in the season — usually brought to notice in September — that it 

 can not interfere materially with the functions of the leaves. The action 

 of the lower surface of the leaf which is of principal importance, would 

 be scarcely affected by its presence. 



