226 [October, 



the migration of June 10th was composed of survivors of that of 



the 5th, which had passed the intervening days and nights at sea. — 

 E. MoLachlan]. 



AORION HASTULATUM, Charp., A NEW BEITISH DRAGON-FLY. 



BY ROBERT McLACHLAN, F.R.S., &c. 



Amongst some Odonnta taken in the north of Scotland this year 

 by Col. Yerbury, and kindly given to me by him, 1 find one ^ Agrion 

 from Aviemore, June 28th, that I identify with A. Jiastulaimn, Chp., a 

 species which, from its known distribution, should certainly occur 

 here. As the appendages have become rather obscured in drying, and 

 also in order to obtain the benefit of a younger and keener eyesight, I 

 submitted the specimen to Mr. Morton for his opinion, having moreover 

 in mind the fact that this summer he made extensive personal acquaint- 

 ance with the species in Norway : he is unhesitatingly of opinion that 

 the individual is Jiastulatum. It is not my intention here to go ex- 

 tensively into the characters that separate the ^ of A. liastulatum 

 from that of Enallagma cyathigerum (the only case in which confusion 

 is possible), but I note briefly a few : — 



On the head the " post-ocular " spots are more elongate in liastulatum, and are 

 connected with the occipital line. On the prothorax there are not the two blue 

 spots (one on each side) seen in cyathigerum ; the posterior margin forms an obtuse 

 angle in the middle (very important), instead of being nearly semicircular as in 

 cyathigerum. On the sides of the thorax the infra-humeral bronzy-black band is 

 practically of the same width throughout ; wliereas in cyathigerum tliere is an 

 obtuse tooth-like projection on its lower edge anteriorly. The spot on the second 

 abdominal segment is distinctly hastate (of a form I have never quite seen paralleled 

 in the numerous varieties of cyathigerum), with a narrow tail or pedicel, and usually 

 with a detached isolated black line on either side (but these lines are wanting on the 

 Scotch example before me). Finally, the inferior appendages arc very much shorter 

 and blunter, and differently formed (in cyathigerum they are long, sub-conical, and 

 Bub-forcipate). 



I have stated that the black lateral lines on the second segment 

 are wanting in my native example. In looking over the small auiount 

 of material I possess for the species, I find these lines are equally 

 absent in a (J from Konigsberg given me many years ago by Dr. 

 Hagen : Mr. Morton says they are frequently absent in individuals 

 from Norway. Let us hope another year will furnish abundant con- 

 firmatory evidence of the occurrence of this interesting species in 

 Scotland. The name has been already included in our lists, having 

 been introduced by Stephens, but in error. 



Lewisham, London : 



September I5th, lOdO. 



