224 PROCEEDINGS OF THE ACADEMY OF [May, 



With antenodal No. 3 only: 



Ischnura denticollis (teratological cf). 



With antenodals Nos. 3 and I^: 



Ischnura denticollis (teratological 9 ) . 



With antenodals Nos. 2, 4, and another: 

 Ischnura granti (type 9). 

 Pyrrhosoma nymphula (teratological 9 ) . 

 Thaumatoneura (normally) . 



With antenodals Nos. 2, 4, and two or three others: 

 Thaumatoneura (occasionally) . 



With antenodals Nos. 2, 4, 5, 6, and 7: 

 Phenacolestes mirandus. 



Although Phenacolestes parallelus is believed to have had six 

 antenodal cross-veins, it has not been possible to place it in the 

 table, as no information has been given concerning the position of 

 the veins in relation to the arculus. 



Looking at the number and arrangement of the antenodal nervures 

 alone, and without having regard to any other considerations, it 

 would appear that among recent genera Thaumatoneura bears the 

 closest resemblance to Phenacolestes. Moreover, this resemblance 

 is accentuated when, as sometimes happens, a fourth, or even a fifth, 

 antenodal is present. But of course the venation of the spaces lying 

 between the nodus and the base of the wing is only one of many 

 characters which must be studied in attempting to arrive at the true 

 affinities of Phenacolestes, and for the present it is perhaps advisable 

 to retain in the subfamily Agrioninse this and other genera associated 

 with it. 



In conclusion, I have to thank Professor Calvert for his kindness 

 in suggesting amendments to this paper, and particularly for drawing 

 my attention to the two Mexican specimens of Ischnura denticollis 

 recorded by him, and furnishing me with information respecting the 

 British 9 of Pyrrhosoma nymphula contained in his own collection. 



