i 



THE WINGS OF TRICHOPTERA 313 



the fibula (Fig. 323). The axillary furrow is immediately behind the second 

 branch of the third anal vein. It is evident that this fibula is fitted to 

 clasp the anterior tuberosity of the hind wing. 



There are two facts that indicate that this is the most primitive form 

 of fibula that exists among the living Phryganeina: first, the generalized 

 condition of the wing-venation of Rhyacophila; and second, the fact that 

 this fibula is identical in structure with that of Mnemonica, one of the most 

 generalized of the terrestrial Trichoptera. It is evident that Rhyacophila 

 and Mnemonica resemble in the venation of their wings and in the form of 

 their fibulae the stem form from which the Phn-ganeina and the Microp- 

 terj'gina have been evolved. 



When more specialized Phrs'ganeina are studied it is found that there is 

 a marked reduction in the size of the fibula and a modification of its form. 

 In Hydromanictis, for example, the posterior lobe of the fore wing (Fig. 322) 

 is greatly reduced in size and has little appearance of being a fibula. It is 

 evident that the uniting of the two wings of each side is being attained in 

 other ways than by a fibula alone. In some cases this is by the overlapping 

 of the wings; in some cases as in Phanostoma and Leptocerus there is a 

 series of prominent hamuli on the costal margin of the hind wing; and in 

 others, as in Gcera, there are strong spines borne at the humeral angle of the 

 hind wing, which probably function as a frenulmn. 



SUBORDER MICROPTERYGINA 



The Terrestrial Trichoptera 



The suborder Micropteiygina includes those Trichoptera in which the 

 wings are clothed with scales, the tracheation of the wings is preserved, and 

 the lar\'se are not aquatic; it is represented b>' a single family, the Micro- 

 pterygidte.* 



The Micropterygidas is a small family of minute moth-like insects which 

 are generally believed to belong to the order Lepidoptera, although several 

 writers have suggested the close affinity of these insects to the Trichoptera. f 



*The genus Microptcryx and its allies were long considered as constituting a single 

 family the Micropterygida;. In 1894 Chapman proposed the separation of this family 

 into two families, the Alicropterygidfe and the Eriocephalida; (Trans. Ent. Soc. Lond. 

 1894, p. 336). In 1912 Meyrick in his monograph of this group (Genera Insectorum, 

 Fascicule 132) regards it as constituting a single family, the Micropterygidae, which he 

 divides into three subfamilies as follows: the Mnesarchajinac, which includes a single 

 genus, MnesarchiEa, represented by three species in New Zealand; the Eriocraniinae, 

 which corresponds to the Micropterygidae of Chapman; and the Micropteryginae, which 

 corresponds to the EriocephaHdae of Chapman. This shifting of family or subfamily 

 names is due to the conclusion that the generic name Eriocephala is a synonym of 

 Micropteryx. For the sake of simplicity I follow Meyrick in regarding the Microptery- 

 gina as including a single family, although it is highly probable that ultimately the 

 mandibulate and liaustilate members of this group will be placed in separate families. 



fN'ote especially the remarks of Dr. Sharp and Mr. McLachlan (Proc. Ent. Soc. 

 London, 1896, p. XVII), and Dr. T. A. Chapman (Trans. Ent. Soc. London, 1896, 

 p. 569). 



