1900.] 



Ill 



(Combined meso and metathorax normal). 



Abdomen: it is here that the greatest departure from tlie normal condition 

 exists, the blue being much reduced. Segment 1 practi- 

 cally normal. Segment 2 : the large black capitate or 

 hastiform spot occupies the greater part of the segment 

 above ; its base is very broad, and its anterior edge is , 

 angulate or sinuate ; on each side it has a broad pro- 

 longation connected with an irregular line, enclosing a 

 semicircular blue space at the base (see figure). On 

 segments 3 and 4 above, the black occupies the basal 

 half, but apicaljy it is produced into a lanceolate pro- 

 longation to the anterior margin ; on the side of these 

 segments the blue predominates. Segments 5 to 10 

 {thus including 8 and 9, which are usually wholly blue) 

 are practically wholly black, but on 5 to 7 there is an 

 apical blue spot (diminishing in size), divided into two 

 by the dorsal crest. The sides of the ventral suture, 

 nearly throughout, glaucous. 



That considerable variation exists in the form of the dorsal spot 

 on the 2nd segment in U. cyathigerum is well known, and the extension 

 of the black on the succeeding segments is also liable to variation, but 

 in neither case am I aware of anything on record approaching this 

 specimen. Especially noticeable is the fact that segments 8 and 9 above 

 are wholly black. 



Perhaps the nearest recorded variation is in specimens from 

 Holland, noticed by Baron de Selys-Longchamps in his " Synopsis des 

 Agrionines," 5™^ legion, p. 91. And Agrion elegantulum, Zett. (Ins. 

 Lapp., 1043), should not be altogether forgotten. Neither of the 

 Scandinavian monographers (Johansson, 1859, and "VVallengren, 1894) 

 succeeded in identifying this insect, although both admitted it. And 

 De Selys (Ann. Soc. Ent. Belg., xxxi, p. 70, 1887) alludes to it as 

 something " que Ton n'a plus retrouve et dont les exemplaires commu- 

 niques par le Dr. Hagen se rapportent a plusieurs especes connues, 

 notamment au cyathigerum." 



Mr. Morton is of opinion that he took his insect at a small ele- 

 vated mountain loch in company with normal cyathigerum, but he did 

 not recognise anything unusual at the time, so the precise spot in 

 Glen Lochay remains slightly doubtful. 



Explanation of figures. ~^\g. K, segments of abdomen 1-3 from side, x 4; 

 B, abdomen above, x 2 ; C, segments 1-2 above, x 8. 



Lewisham, London : March, 1900. 



