28 



MOKPHOLOGV, ETC., OF THK MICKOPTEUYGIDjE, I., 



genera of the Orders Mecoptera and Planipennia. The scales of 

 the Micropteryyinoe and Eriocraniince are of similar structure, 

 though those of Mnesarchcea are more highly specialised. 



We can only conclude from this that, on the characters con- 

 sidered in this Part, there is no justification whatever for re- 

 moving the Micropterygince to a separate Order Zeugloptera. 



(2) Are the Jfirropterygidw terrestrial Trichoptera ? 



Professor Comstock relies almost entirely upon the venationul 

 scheme and the form of the jugal lobe (which he calls the fibula) 

 for the justification of his removal of this group to the Order 

 Trichoptera. 



The complete discussion of the relationship between the wing- 

 venational schemes of the Trichoptera and Lepidoptera has been 

 selected by me as a necessary portion of the argument of the 

 paper on the Panorpoid Complex, Part iii., which, I trust, will 

 be available in print at the same time as this paper. Hence 

 there is no need for me to go into the same details here, but 

 simply to refer the reader to that paper. The results, however, 

 may be given here, with just two illustrations that will carry 

 conviction. There can be no doubt that the venational schemes 

 of the Triclioptera and Lepidoptera are identical in all essential 

 particulars. In Text fig. 13, I give the tracheation of the base 

 of the pupal forewing in the Hepialid Charagia exiraia Scott. If 

 this be compared with the tracheation of the forewing of the 

 pupa of Eriocrania (Text -tigs. 1, 2), it will be seen at once that 

 there is no difference of importance. Charagia is the more 

 specialised, in that trachea Rs has been split back right to its 

 very origin on the alar trunk, and the three anal veins are some- 

 what reduced. The variability in the condition of the anal 

 venation in the forewings of Lepidoptera is very great, and in 

 contrast with the specialised and very constant condition found 

 in the forewings of all Trichoptera, in which 2A loops up with 

 1A, and 3 A with 2 A. In Lepidoptera, exclusive of the Micro- 

 pterygidie, 3A is either very reduced or absent, and does not loop 

 up with 2 A. But 2 A is frequently found to be looped up with 

 1 A, giving the so-called "forked anal vein." Now the J/icro- 

 pterygidm as a whole repeat on a smaller scale this variability, 



