72 Annals Entomological Society of America [Vol. VI, 



specimens it is wholly lacking. Finally in such forms as the 

 European 0. testacea (Fig. 7c) the base of M3+4 has migrated 

 farther back on Cui and in this position its true nature as a part 

 of M3+4 is far from obvious. In such a case the vein becomes 

 virtually a cross vein and migrates according to the mechanical 

 stress in flight without reference to the distal part of the vein 

 which is left stranded with a new basal connection. Other 

 instances of this sort occur in the Trichoptera and they are not 

 uncommon in other orders. 



The facts here presented may be of some significance in 

 their bearing on the question of the systematic position of the 

 Helicopsychinas. This subfamily has always been placed in 

 the Sericostomatidae because of the unequal number of segments 

 in the palpi of the male and female, though it has always been 

 clearly recognized that it bears no close relationship to any of 

 the heterogeneous groups included in that family. Thienemann, 

 Ulmer, and Martynov have each suggested that a new sub- 

 family should be erected for the genera Helicopsyche, Tetano- 

 nema, and Saetotricha, and Ulmer and Martynov have during 

 the past year almost simultaneously described the subfamily 

 Helicopsychinae, Ulmer's description being slightly the earlier. 



Fig. 8. Venation of apical part of fore wing of Sericostoma sp. 



In his recent work on the fossil forms Ulmer lists the Heli- 

 copsychinae among the Sericostomatid^ but in this work (p. 376) 

 he makes the first suggestion that these forms may possibly 

 show affinities to the Leptoceridae though he gives, so far as I 

 can find, no reason for the statement. What has been given 

 above certainly confirms the impression which Ulmer has 

 stated since in the HelicopsychinEe, the Molannidas, and the 

 Leptoceridae, R5 shows an increasing tendency to migrate upon 

 Mi+2 — a condition not seen elsewhere in the Trichoptera, 

 though the sharp angle in R5 seen in Sericostoma (Fig. 8) and 

 other forms might be regarded as a beginning of that tendency. 



