182 



ME. R. m'lACHLAN on THE NEUEOPTEEA 01* 



tangible difterences in the examples from the islands, as compared 

 with others from Europe &c. A c? in De Selys's collection cer- 

 tainly seems to have the superior appendages more attenuate at 

 the apex ; but I think it is owing to the turn they have taken in 

 drying, and hence illusory. 



? Akax MAUEiciAi^us, Riimlur . 



Madeira. 



I possess one S Anax obtained from a dealer, and indicated 

 from Madeira, that is probably referable to mauricianus ; other 

 insects accompanying it were certainly Madeiran. 



Hageu (Yerh. z.-b. Gesellsch. AVien, svii. p. 44) doubts the 

 distinctness of mauricianus from formosus ; possibly it is only a 

 case of slight variation ; still there are certain structural pecu- 

 liarities. Eambur, in describing his mauricianus (Nevropteres, 

 p. 184), alludes to several colour-differences that are probably 

 illusory for the greater part. As to structure, he mentions, inter 

 «Zi«, the following points : — "Abdomen plus long, plus grele ; " 

 superior appendages internally " plus profondemeut sinueux en 

 approchant de I'extremite, qui est plus ctroite ; " inferior appen- 

 dage " un peu plus court ;" " pterostigma beaucoup plus petit ; " 

 also " nervure costale chez le male n'etait pas jaune anterieure- 

 ment." In all these points my example fully agrees ; but in some 

 others — such, for instance, as the absence of little tubercles on 

 the margin of the tenth segment — it does not accord. De Selys 

 has kindly lent me a series of examples bearing upon the question, 

 including one of Eambur's types from Mauritius *. This agrees 

 with the description in most of the points mentioned, but disagrees 

 in others (as does my example). The costal nervure is yellow 

 externally in this, black iu mine (I do not think I have seen a 

 true formosus in which this nervure is black externally ; but it 

 may occur in very adult examples). The inferior appendage is 

 still shorter in mine, scarcely longer than broad ; in this it appears 

 to agree with examples from De Selys, labelled by him " mauri- 

 cianus, race hrevistigma" received from Madagascar and Bourbon ; 

 and even the pterostigma in my example more approaches these. 

 Probably it would be safer to refer formosus, mauricianus, and its 

 race Irevistigma, all to one species {formosus) ; but we yet require 

 more extended local information f. 



* Probably other types are in the Oxford Museum ; but that iu De Selys's 

 collection should be from the same source, i. c. "M. Marchal." 

 t Hagen (Verb. z.-b. Gesellsch. Wien) alludes to the condition of the median 



