MARCH, 1862. 193 



The body tapers somewhat from the thoracic rings. The 

 larva was not taken from the mine for description. 



The imago of this species is undescribed, and although 

 I secured cocoonets last fall, which may produce imagos in 

 the spring, I shall be glad if some new observer rears imagos 

 in the coming summer and records a description of them. 



Sycamore miner, No. 3, mines, at first, in a very narrow, 

 transparent track, having a blackish central line of frass ; 

 the tract being usually much contorted. At this stage of its 

 larval life, which is its earliest period, the miner can scarcely 

 be detected by the naked eye. Three or four days before 

 pupation, the larva begins to enlarge the linear mine into a 

 blotch. This enlargement takes place most often over the 

 course of the old linear mine, the latter half of which furnishes 

 the basis of the blotch, and hence leaves within it a blackish 

 frass-line. The edges of the blotch are irregular; in the 

 mine of Platanella the blotch is circular or nearly so, and 

 the early portion of the mine is filled with frass, while the 

 blotch is formed by dilating the linear tract, after it becomes 

 five or six lines long. 



The larva, when young, is transparent ; colour white, tinged 

 with greenish, with the thoracic segments swollen, giving it 

 a fusiform appearance. Subsequently it becomes of a pale- 

 green colour, retaining, however, the swollen thoracic rings. 



In order to insure success in rearing these larvae, one must 

 be careful that an excess of moisture does not condense on 

 the sides of the vessels in which the leaves containing them 

 are kept. When the larvae are full fed, they abandon their 

 mines in order to weave their cocoons, and if there is much 

 moisture on the sides of the vessel, the larvae will be drowned 

 in it as they endeavour to ascend its sides. When this 

 happens, or when the larvae are disabled by a few hours' sub- 

 mersion in this moisture, the observer is not only discouraged, 

 but his care and attention are lost. 



This accident has happened to me very often. In order 

 to avoid it I have found that if the layer of moist sand is 



o 



