BY R. J. TILLYARD. l03 



(2) The Micropteryyidce are terrestrial Trichuplera. This is 

 the new view formulated by Professor Comstoek. 



'3) The genus Micropteryx belongs to a new Order Zeugloptera. 

 Eriocrania, on the other hand, is a true Lepidopteron. This is 

 Dr. T. A. Chapman's view. 



It is the object of this paper to try to discover which of these 

 three views is correct; or, if none of them be acceptable, to 

 try to find a substitute for them. The decision to be made is 

 of the very greatest importance, not only in determining the 

 vexed question of the true position of these archaic insects, but 

 also because it radically affects the definition of the Archetype 

 of the Order Lepidoptera; and hence, our decision as to the 

 origin of that Order as a whole. 



• The first part of this paper is confined to the study of the 

 wings alone. The rest of the Morphology of the Micro pterygida 

 will be dealt with in a series of succeeding Parts. 



Part i. — T he Wings of t h k M i c r o p t k r y g i d je. 

 Section i.— The Wing-venation. 



In his book on the Wings of Insects (3, pp.314-318) Professor 

 Comstoek deals with the venation of this group. No attempt 

 has been made to study the pupal tracheation, probably because 

 the necessary material was not available. But drawings are 

 given of the tracheation as partially preserved in a pair of cleared 

 and mounted wings of Mnemenica sp., which offered very striking 

 results, and on which Professor Comstoek 's conclusions are chiefly 

 based. 



My -request to Dr. Chapman for cocoons of Eriocrania con- 

 taining living larvae was made principally with the object of 

 obtaining the living pupa and studying the tracheation of the 

 wings. Dr. Chapman very kindly obtained for me the larvae in 

 the spring of this year, and fed them until they went into the 

 ground to spin up. In the South of England, these larvae, ap- 

 parently, are full fed about Midsummer, and soon go into the 

 ground, making their tiny oval cocoons of grains of sand spun 

 together. In these they remain until the following February, 

 when they pupate, emerging as imagines in the spring. Dr. 

 Chapman dug up the first lot of cocoons, fifteen in number, 



