650 THE PANORPOID COMPLEX, ii., 



tlie Hetereiieura. Tliese liave already been very fully dealt with 

 by many authors. 



Returning* to the Froiofheoridit, it is of the very greatest 

 interest to note that traces of the original archedictyon are still 

 to be found in this archaic family. In Text-fig. 34, and Plate 

 Ixviii., Hg. 1 1, J show the very definite archedictyon that is to be 

 seen above the radius. Here, not only do the macrotrichia 

 (which, in this region of the wing, are all scales, not hairs) show 

 very clearly the original arrangement of the mesh work, but there 

 is actually a sliglit thickening and darkening of the membrane 

 forming the archedictyon itself. Allowing for the difference in 

 the sizes of the two wings, this condition in Prototheora is closely 

 similar to that preserved in ArchijKinorpa. Though I have not 



. X>""Vv.)»^:. k ^' ■■:■■ .A .9 





Text-fig. 84. 

 Portion of the aphantoneuric archedictyon preserved above the radius of 

 the forewing in Profotheora petrosema Meyr. ; ( x 180). (>See also 

 Plate Ixviii., fig. 11). 



been able to find so good an example of an aphantoneuric arche- 

 dictyon as this, anywhere else within the Order, yet there are 

 numerous cases in which what appears to be the last remnant of 

 the archedictyon can be seen in proximity to the veins, usually 

 in the form of a series of slightly darkened and thickened spurs 

 projecting almost at right angles to the main vein upon which 

 they abut. 



Reviewing the above evidence, it would seem that, in the 

 Lepidoptera, the foi-mation of scales must have begun befoi-e the 

 complete disappearance of the archedictyon. This suggests that 

 the scales in this Order must be an exceedingly archaic character, 

 originating in a specialisation of some type belonging to an 

 ancestral Order in which the archedictyon still persisted. 



