42 DR. BRACKENRIDGE CLEMENS' LETTERS. 



entirely, that Brcnthia is very like the genus Simacthis. 

 These genera doubtless belong to the same group. I cannot 

 perceive, however, why Simacthis is placed in the group 

 Pyralidina, and cannot imagine what considerations have 

 governed European systematists in determining this to be the 

 natural and proper place for the genus. 



After having attentively examined the specimens of iV. 

 angulifasciella, which you sent me, and comparing them 

 with those of N. rubifoliella in my possession, I do not 

 believe the two insects to be distinct. The structure of the 

 wings is the same in both ; in each there is a closed discoidal 

 cell near the base of the wing, thus differing from your de- 

 lineations of the wing structure of the genus in Insect. Brit. 

 The silvery fascia of the fore-wings has less tendency to be 

 interrupted in the middle in Rubifoliella, and is somewhat 

 more curved towards the base of the wing ; and the only dis- 

 tinction I can perceive between them is, that the cilia of the 

 fore-wings in Rubifoliella are less white, or rather I should 

 say not whitish, and that it is at least one-third smaller than 

 Angulifasciella. I have failed to meet with our larva this 

 year, and indeed during the fall month, in which I expected 

 to find it, have been unable to look for it. 



In July last I found a single specimen of an imago 

 belonging to the genus Opostega. It differs structurally in 

 no respect from the European species of this genus; its 

 ornamentation is very simple, the entire insect being silvery 

 white, with a minute black dot at the extreme apex of the 

 fore-wings. I have not yet published a description of it, but 

 have named it O. JVapceella. It may possibly be identical 

 with or approach closely some of your species. 



My time has been so occupied during this season that the 

 number of observations I have been able to make on larva? 

 has been very small and unimportant. 



A few days ago, however, I found on oak a case-bearing 

 larva that puzzles me. I am undecided whether it is a 

 Coleophorous or Coleopterous insect. It does not mine the 

 leaf, but feeds on the under surface, leaving the net-work of 



