168 LEAF-MINING INSECTS 



Chrysopelcia 



Our two northern species of this genus mine the leaves 

 of the hop hornbeam. The best available account of the 

 mining habits of one of them, C. ostryaella, is the old one by 

 Clemens sent in a letter to Stainton in 1859 and published 

 by the latter (1872) which we reproduce herewith. 



I send you a leaf of Ostrya trirginica, containing what to me is a 

 novel mine. I found it for the first time a few days ago, when 

 looking for cocoons intended for you. I should be glad to learn 

 whether you know of any larva having a similar habit. The mine 

 begins along the midrib, and scarcely ever exceeds the limit of the 

 two veins, between which it is first commenced. Its peculiarity 

 consists in the construction of lateral walls of "frass" within the 

 mine, that are extended as the mine increases in length, forming a 

 tube, transparent above and below, which leads to an opaque one 

 alongside of the midrib of the leaf. When the larva is alarmed or 

 disturbed it retreats along this way and conceals itself under the 

 opaque portion along the midrib. It quits the leaf to transform, 

 and weaves a little ovoid cocoon. 



Cosmopteryx 



We introduce this genus of dainty leaf-mining mothlets 

 with Busck's (1906) brilliant description of them: 



The little moths belonging to the genus Cosmopteryx are prob- 

 ably familiar to anyone who has collected and observed insects 

 in nature. Who has not occasionally on a warm midsummer day 

 met with a slender little streak of gold and silver sitting in the 

 sunshine on a leaf in a protected corner and twirling its long white- 

 tipped antennae in graceful motions? If, when examined very 

 closely, it is found to be a smooth shining little moth, brown with 

 silver lines on palpi and antennae, and with a striking broad golden 

 or orange fascia across the outer half of the wing, bordered on 

 both sides by bright metallic scales, then you have a Cosmopteryx. 



Most of the species may at once be recognized by this character- 

 istic ornamentation alone, without structural examination. 



