BY R. J. TILLYARD. 213 



hia. This enjoys the unique position of being the most Agrionid- 

 like of all CalopterygidcE. It is the most highly specialised genus 

 of the subfamily EpallaghicB. That subfamily is, however, the 

 most archaic in the family. Hence, the phylogeny of Diphlebia 

 is of such a nature as to offer good hopes for the solution of some 

 of our problems. These solutions could not, in any case, be 

 allowed to rest on evidence from a single genus, or from two or 

 three closely related genera. Now the genus Calopteryx, which 

 also — but in a direction quite different from that of Diphlebia — 

 combines high specialisation with a number of archaic characters, 

 is available in Europe. I, therefore, wrote last year to Dr. Ris, 

 of Switzerland, urging him to do his utmost to secure larvpe of 

 Calopteryx in the spring, with a view to photographing the 

 tracheation of the larval wing. Meanwhile, I searched assidu- 

 ously for the rare larva of Diphlebia lestdides Selys, of which I 

 had previously found only one specimen in the course of nine 

 years' collecting. 



A further difficulty confronting us was the fact that the wing- 

 cases of Calopterygid larvae are tough, hairy, and opaque, offering 

 very poor material for photographic work. l)r. Ris had already 

 mentioned this to me as a point which had previously deterred 

 him. I suggested to him that it would be necessary to secure 

 larvse that had just undergone ecdysis, so as to photograph them 

 before the wings had had time to harden up and become opaque. 

 My letter reached him in April, 1914. A few days later, he 

 went to a known locality for C. splendens Harris, and was both 

 surprised and delighted to find a number of larvae exactly in the 

 most suitable stage. The wing-tracheation of these specimens 

 was photographed. I have to thank Dr. Ris for his kindness in 

 offering me these beautiful photographs for use and publication 

 in this paper (Plate xxxiv., figs. 1-3). 



Meanwhile , the search for Diphlebia larvae went on without 

 result until September last. For their discovery, I am indebted 

 to the kindness and energy of Mr. F. W. Carpenter, M.A,, of 

 Sydney Grammar School. While staying with me at Went worth 

 Falls, he kindly offered to make an exhaustive search of the 

 rocks in Lilian's Bridge Creek — a locality which I had indicated 



