120 MORPHOLOGY, ETC., OF THE MICROPTRRYGID^, i., 



chaia might well be a direct derivative from Eriocrania, con- 

 siderably more specialised, and, therefore, rightly placed in a 

 separate subfamily. In the next section, it will be seen how 

 very different the scales of this genus are from those of all the 

 rest of the Micropterygidm. If, therefore, it should turn out 

 that the life-history of this genus, when discovered, is very dis- 

 tinct from that of both Eriocrania and Micropteryx, there would 

 then be a strong case for its separation out as a distinct family 

 Afnesarchceidce, characterised by the combination of the loss of 

 the forking of R2+3, together with the remarkable specialisation 

 in the structure of the scales. As these latter are of the greatest 

 importance in considering the claim of the Micropterygidce, to be 

 included in the Lepidoptera, I shall deal with them fully before 

 comparing the wings of this family as a whole with those of 

 Lepidoptera and of other Orders. 



Section ii. The Scales. 

 In all the Micropterygidce, both microtrichia and macrotrichia 

 are present, as in all the more archaic members of the Orders 

 Megaloptera, Planipennia, Mecoptera, Diptera, Trichoptera, and 

 Lepidoptera. The presence of microtrichia in itself is, therefore, 

 no argument in favour of the inclusion of this family in any one 

 of these Orders, in preference to any other. But the fact that they 

 are of exceptionally small size, as they are in all Lepidoptera that 

 possess them, must speak for the Lepidopterous nature of the 

 family. In the same way, the presence of macrotrichia in itself 

 is no argument in favour of any one of the six Orders as against 

 another; but the fact that most of them are highly specialised 

 as scales is of the greatest importance. 



Various authors have depreciated the value of the presence of 

 scales in this respect, by remarking that scales also occur in the 

 Trichoptera and Diptera. They forget to add, however, two 

 very important facts; firstly, that scales only occur in a few 

 specialised representatives of these two Orders, and are certainly 

 not to be found in the most archaic groups of either Order; and, 

 secondly, that, in the Trichoptera at any rate, the scales are of a 

 much more primitive type, even in the highest genera. Leaving 



