314 



THE WINGS OF TRICHOPTERA 



(a) THE VENATION OF THE WINGS OF THE MICROPTERYGID.^ 



The family Micropterygidse has been monographed recently by Mey- 

 rick ('12), who recognizes eight genera represented by fifty-five species. 

 This author calls attention to the resemblance of some of the more general- 

 ized forms, as Sabatiiica, to Rhyacophila; but does not suggest the trans- 

 ference of this family from the Lepidoptera to the Trichoptera. 



The wings of a species of Mnemonica (Fig. 324) can be taken as illus- 

 trating the more generalized type of wing-venation found in the Microp- 

 terygidse. The fore and hind wings are quite similar in form and venation. 

 The subcosta is distinctly forked in the fore wing and slightly so in the hind 

 wing. Vein Ri in both wings bears an accessor}^ A^ein, vein Ri^; the pres- 



Sc, Sr. ^i 



2d A istA Cu2 <^«' 

 Fig. 324. — Wings of Mnemonica sp. 



ence of this accessory vein is limited to the more generalized^members of 

 the family. The radial sector is four-branched in both fore and hind wings; 

 in the fore wings of the individual figured here vein R3 arises from vein 

 R4+5, but this is an exceptional feature; usually the forking of the radial 

 sector is dichotomous. The media is reduced to a three-branched condition 

 in both fore and hind wings, by the coalescence of veins M3 and M4. In 

 the fore wings veins Cu and ist A coalesce at the base of the wing; the base 

 of the free part of vein Cu appears like a cross- vein; and a serial vein is 

 formed by the base of media, the posterior arculus, and the longitudinal 

 part of the cubitus. In the fore wings the tips of the second and of the first 

 two branches of the third anal vein coalesce, forming a single vein, which 

 reaches the margin of the wing near the tip of the first anal vein. 



