Vol. XXvii] ENTOMOI.OGICAr, NEWS. I7I 



lem to taxonomists. De Selys in 1873, largely on the size and 

 form of the male abdominal appendages, divided the asso- 

 ciated genera into 2 major groups, the latter of which was di- 

 vided into 5 subgroups, one of these being in turn divided into 



2 groups and one of these subdivided on geographical grounds. 

 I believe that these groupings have little basis in fact, but that 

 two groups of real taxonomic value can probably be distin- 

 guished on the basis of the number of cross-veins between Mi- 



3 and M4. In the larger number of genera the number is re- 

 duced in the front wings and in the hind wings there is nor- 

 mally only one, which is strengthened and defmitely olaced. 

 In the remaining genera the number of these cross-veins is 

 relatively larger (the complexity of venation must be taken 

 into account), and in the hind wing there are always tivo or 

 more, instead of one definitely placed cross- vein. These 

 genera known to me are Macrogomphiis, Microgomphus, Lep- 

 togomphus, Epigomphiis, Cyanogomphus and Agriogomphns 

 — a group of striking and remarkable forms. Microgomphus 

 and Agriogomphns have much in common, including the un- 

 symmetrical forking of M1-2 and M3, and the single row of 

 cells in the anal area of the front wings ; in Microgomphus 

 there are two rows of postrigonal cells, one row in Agriogom- 

 phns. The remaining genera have a basal antenodal of the 

 second series present in all wings. In only one, Cyanogom- 

 phus, has the stigma a brace vein, at;d in this genus alone the 

 distal thickened antenodal is the fifth, being more distal in the 

 others. In Epigomphns and Macrogomphus there are two 

 cubito-anal cross-veins in addition to tlie inner side of the sub- 

 triangle. 



To summarize, the genus Cyanogomphus, as a member of 

 the legion Gomphns, may be venationally defined briefly as 

 follows: Cross-veins between M1-3 and M4 numerous; stigma 

 with a brace vein; M4 and Cui divergent; basal subcostal 

 cross-vein of second series present ; one cubito-anal cross-vein 

 in addition to the inner side of the subtriangle; anal area of 

 front wing proximally one cell wide, distally two or three 

 cells wide ; three postanal cells in hind wing, distal to postanal 



