gO [February, 



As stated above, Mr. MeLachlan considers Thaumatoneura a 



C alopter ygine. While I hesitate to differ from such a high and 



excellent authority, I have come to the conclusion that this genus is 



more closely related to certain members of the subfamily Agrionince. 



The evidence on either side of this question appears to be as 



follows : — 



In favour of Us Calopteuygine affinities. 



1. — The number of ante nodal cross-veins, 3 — 5. 



2. — The density of the reticulation, shown not only by the presence of supple- 

 mentary sectors between all the principal ones, but also by the presence of cross- 

 veins in the post-costal area beginning at, or in front of, the level of the arculus. 



In favour of its Agrionine affinities. 



3. — The point of separation of the median sector from the principal sector, 

 which is distinctly nearer (f — f) to the nodus than to the arculus. 



4. — The position of the nodus, at about one-fifth the length of the wing. 



Passing now to discuss these features, character (1) is unquestionably that 

 commonly employed as the chief diagnostic of the Calopierygince, since the 

 Agrionince, with but few exceptions, possess but two antenodal (or antecubital) 

 cross-veins. However, at least two Agrionine genera are now known, Neurolestes, 

 Selys,* and Neuragrion, Karsch,f in which three antenodals normally exist. The 

 lowest number of antenodals hitherto known for the Calopterygince is five in the 

 genus Micromerus. Since the number of antenodals in Thaumatoneura varies from 

 three to five, we have a complete transition from the Calopterygince to the 

 Agrionince in this particular respect. 



(2). I am not aware that any Agrionince show a density of reticulation equal 

 to that possessed by Thaumatoneura, but Megaloprepus approaches it quite closely 

 in the number of supplementary sectors, and in having the cross-veins of the post- 

 costal area beginning often in front of the level of the apex of the quadrilateral. 

 But since many Caloptergginai (legion Libel/ago, Dicterias, etc.) possess a quite 

 simple reticulation, density of reticulation cannot be accepted as a chief Calop* 

 ierygine feature. 



(3). The Calopterygince have the point of separation of the median and 

 principal sectors much nearer to the arculus than to the nodus, the reverse being 

 the case in the Agrionince, with the exception of the legion Lestes, Selys, in which 

 latter the condition is the same as in the Calopterygince. The nearest approaches 

 among the Calopterygince to the condition found in the Agrionince (exclusive of 

 Lestes) seem to be in Heliocharis, where the median sector separates at one-third 

 the distance from the arculus to the nodus, and the Japanese Palaophlebia, Selys, 



* A West African form, of the legion Podagrion, Selys, having three antenodals on all the 

 wings, the third one placed between the other two of most Agrioniact. Mem. Couron. Acad. 

 Sc. Belg., xxxviii, p. 70, 1886. 



+ Also of the legion Podagrion, from Ecuador, having three antenodals on the hind-wings 

 only, the third being likewise median and confined to the subcostal space. Soc. Ent., vi. p. 100, 

 1891.' 



