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THE WING-VENATIOX OF LEPIDOPTERA. 

 (PRELIMINARY REPORT). 



By R. J. TiLLYARD, M.A., B.Sc, F.L.S., F E.S., Linnean 

 Macleay Fellow of the Society in Zoology 



(Seven Text-figs.) 



This short paper is an outline of one portion of a paper upon 

 which the author is engaged, to be entitled " The Panorpoid 

 Complex: a critical study of the phylogeny and inter -relation- 

 ships of the Holometabolous Insects, with special reference to the 

 four Orders Mecoptera, Trichoptera, Lepidoptera, and Diptera." 

 The genesis of the paper was the discovery of a remarkable large 

 fossil insect, of a generalised type, from the Trias of Ipswich 

 (Q. ). In the structure of the wing-venation and wing-membrane 

 of this insect, the writer recognises the nearest known approach 

 to the true ancestor of these four Orders. The complete paper 

 will be an attempt to show the diverging lines of descent of the 

 four Orders from their common ancestor. 



The fossil wing-form, which may be termed the Protoniecojyt- 

 eroiis form, is exceedingly complicated, both in the actual vena- 

 tion, and in the structure of the membrane. The essentials of 

 the type may be defined as follows : — 



(i.) Wing -membrane with an abundant but obsolescent polygonal 

 meshwork of small areolets or cellules, of Palseodictyopterous 

 origin. Upon the angles of the areolets (and also upon the main 

 veins), large hairs or bristles were developed. These are termed 

 macrotrichia. Upon the whole wing-surface, much smaller and 

 more abundant minute hairs, or microtrichia, are arranged. 



(ii.) Wing-venation oi Panorpid type, fore- and hind wings sub- 

 equal. The essential characters of this venation are, (a) the 



