BY R. J. TILr.YARn. 321 



advanced genera of many families. In Syiithemis the stigma is 

 usually unbraced, as in S. re^/ma (fig.l3), but -S'. macrnstigma 

 (fig.l5) shews a distinct advance towards bi-acing, while .S". clavi- 

 cidata(^Q^.W) possesses a bracing vein. 



Freak-venatio^i in the Genus' — I do not recall, in an}' other 

 odonate genus, such remarkable fi-eak-venation as may be found 

 in Synthemis. Especially is this " freaking " to be found in the 

 region of the triangle and arculus. Passing by such small 

 "freaks" as a four-sided triangle, which is especially evident in 

 my series of ^S'. tasvianica, n.sp., and S. cyanitlncta, I come to 

 three remarkable freaks, which I have figured. In the right 

 forewing of a specimen of -S'. leachii ^(fig.ll), and in the same 

 wing of a specimen of S. cyanitincta 9(tig.l2), I find a freak- 

 variation of the triangle which is of especial interest, as being 

 almost exactly a reproduction of the venation, in this region, of 

 Karsch's remarkable Pentathemis memhranulata. The venation 

 of that peculiar insect is, apart from the triangle, almost exactly 

 that of an Aeschnosoma, and I suggest that the single type- 

 specimen (a female) described by Karsch is nothing more nor 

 less than a freak of that genus. If, in the twenty specimens of 

 S. leachii and in the doze:; ut S. cyanitincta taken by myself — 

 both series from the same district, and dui'ing the same fortnight 

 — two such freaks could occur, surely it is not a great stretch of 

 imagination to think not only that freaks in single wings are 

 common in this genus, but that a lucky collector might capture 

 one with the Pentathemis- tviAn<^\Q in both forewings. Whether 

 variation occurs also in jEschnosoma, sufficiently to justify the 

 application of this assumption to that genus, I cannot say; but 

 it seems at least quite possible. Any entomologist who can get 

 access to the Pentathemis-type should carefully compare the right 

 and left sides of the insect for any other indication of freaking or 

 variation; and any lack of complete .symmetry, especially in the 

 right and left triangles, would go a long way towards establish- 

 ing my contention that this insect is in reality a freak. 



The freak figured in fig. 16, from the wing of a male »S'. regina^ 

 is so extraordinary, that I doubt if the dilferent veins can be 

 23 



