1913] 



Helicopsyche MolannidtB and Leptoceridce 



67 



Attention has already been called to the small corneous 

 point that occurs in the base of cell R4 in almost all Trichoptera. 

 Perhaps the position of this point may be given some weight 

 in the determination of the veins between which it occurs, as is 

 done in the discussion of the venation of the Molannidas and 

 the Leptoceridse given later in this paper. In the case of 

 Helicopsyche the evidence from this source now available is 

 incomplete and apparently contradictory. In Ulmer's figure 

 of the closely related genus Tetanonema (Genera Insect. 

 Fasc. 60, pi. 12, fig. 100) the corneous point appears in its 

 normal position in cell R4 but in his figure of H. sperata (1. c, 

 pi. 11, fig. 97) and in the figures of several related genera 



Fig. 3. a, Radius of the fore wing of Helicopsyche borealis. b, The same 



from H. minuscula (after Martynov). c, Another specimen of 



H. borealis (after Ulmer). 



described in his fine work on the fossil forms it is found in cell 

 2nd R3, that is, in the cell immediately anterior to the one in 

 which it normally occurs. On the other hand this spot is not 

 shown in McLachlan's figures of H. sperata and H. borealis, 

 Martynov does not find it in H. sperata and the study of a 

 large series of H. borealis fails to reveal a single occurrence. 

 Since Ulmer's observations are on material in amber there may 

 be greater chance for error though it seems unlikely that this 

 should happen in several cases. At any rate, Tetanonema and 

 Saetotricha, the only closely related modern forms, should be 

 re-examined in this connection. If Ulmer's figures are correct 

 these cases form the only exception to the rule that the corneous 



