318 PROCEEDINGS OP THE ACADEMY OP 



The anterior wings are pointed (from the outline of the cilia appearing to be 

 elliptical,) the posterior lanceolate. Injthe anterior wings the discoidal cell is 

 acute behind ; the subcostal nervure sends two short branches to the costa, and 

 from the apex of the discoidal cell a single vein to the tip. The median ner- 

 vure sends two veins to the inner margin near the tip. In Desmodiella there is 

 but one subcosto-marginal vein. In the posterior wings both the subcostal and 

 median nervures are simple. 



There are two larval forms in this genus. In the first, the head is much 

 longer than broad, acutely ellipsoidal, with the sides rather thick and rounded ; 

 the body is cylindrical, submoniliform and the thoracic rings somewhat swollen. 

 In the second, the head is thin and flattened, with the mandibles forming an 

 appendage in front ; the body flattened, deeply incised and mammillated on the 

 sides. In both groups there are three pairs of thoracic feet, three of abdominal 

 and a terminal pair, but shorter in the second than the first. 



The larvae mine the upper and under side of leaves, the larvse of the first 

 group usually throwing the leaf into a fold and feeding from the margins of the 

 mine to the center ; those of the second forming a flat mine, sometimes a rather 

 broad linear tract and sometimes an irregular blotch, their mandibles being 

 capable of working only in a horizontal direction. They change into pupa 

 within the mine, some weaving a firm cocoon, some suspended in a web, and 

 some forming a cocoon of grains of excrement and silk, or constructing the 

 outline of the cocoon with them. The cocoons of the second group are shown 

 on the separated epidermis as a circle and an almost hemispherical protuber- 

 ance on the under surface. 



The perfect insects rest with the antennas thrown backward beneath the wings, 

 some with the head slightly elevated, others with the head applied to the surface 

 and the body behind elevated. I think the majority of the species here de- 

 scribed assume the latter position, with variations in the angle formed with the 

 surface on which they rest. 



Table of Species. 



I. W ith an apical spot. 



Without a basal streak. 



Fore wings golden above the fold. 

 2. Robiniella, dark cinereous beneath the fold, sometimes rather silvery. 

 Fore wings pale reddish-saffron, with golden hue. 



4. ^Eriferella, with the first dorsal streak black-margined internally 

 and at tip behind. 



Fore wings deep reddish-orange. 

 10. Obstrictella, with three silvery bands ; apical spot with one or two 

 silvery scales. 



With a basal streak. 

 Fore wings silvery. 

 Basal streak black. 



6. Argentifimbriella, with the streaks decidedly dark-margined ; 

 golden towards the tip. 



Basal streak golden. 

 1. Lucidicostella, with the streaks not decidedly margined ; suffused 

 with golden. 



Fore wings pale golden. 

 Silvery basal streak black-margined. 



7. Obscuricostella, with inner margin at base of the general hue. 



Silvery basal streak unmargined. 



8. Ostryaefoliella, with inner margin at base with a white streak. 



II. W ith an apical spot. 

 Apex concolorous and not dusted. 



[Nov. 



