390 PROCEEDINGS OF THE ACADEMY OF 



united with the antehumeral ; dorsal carina brown-black on its extreme tipper 

 edge ; covering each side of the dorsum, and parallel with that prolongation 

 of the dorsal carina which runs to the base of the anterior wings, are four equi- 

 distant brown-black lines, attaining the suture below, but not quite attaining 

 the carina above, where they are connected each with the adjoining one by a 

 semi-circular brown-black line with its convexity upwards, the middle semi- 

 circle appendiculate above ; on the left side of the dorsum the third line is 

 bifurcate at half its length, and the fourth line is obsolete ; most of these lines 

 are visible to the naked eye, and under the lens they are all very plain, and 

 they convey the impression of being located, not on the exterior surface, but 

 in the interior crust of the thoracic integument ; pleura shaded with brownish 

 immediately behind the humeral suture and under the wings, but with no 

 indication of any stripes ; spiracle deep black ; the rest of the pleura, as well 

 as the sternum, immaculate ; antealar and interalar sinus brown, the two 

 scutella, with a small round piece before them and a piece on each side of 

 them, yellowish. Abdomen long, slender, not expanded at tip, brown-black, 

 its dorsum marked with yellowish as follows : Joint 1 with a round basal spot 

 confluent with a terminal band ; joint 2, which has its earlets yellowish and 

 subobsolete, pale brown before its medial suture, behind which is a lanceolate 

 spot reaching the tip ; 3 7 with a small, obscure, basal triangle, more and 

 more obsolete behind, till in 7 it is scarcely perceptible ; 9 and 10 with a basal 

 transverse line, visible only above, which, as in some of the following spe- 

 cies, is in reality a membranous prolongation of the preceding joint ; late- 

 rally 12 and 8 9 are yellowish ; 9, which is nearly half as long again as 8, 

 and five or six times as long as 10, being more conspicuously yellow ; 3 4 

 have an obscure basal yellowish triangle, with indications of yellowish mark- 

 ings on the succeeding joints ; joint 10 is entirely pale brown both dorsally 

 and laterally, except the membranous basal line. Joint 8 is a little dilated 

 towards its tip, as compared with the preceding joints, but 9 is actually much 

 narrower than the other joints at tip, and no wider than they are at base. 

 Abdominal appendages one and a half millimetres long, brown-black, conical, 

 slender, acute, wide apart at base, directed downwards, slightly convergent, 

 paler beneath, pubescent under the lens, surmounting a pale brown semicircular 

 anal process, which is two-fifths their length and is directed downwards. The 

 vulvar lamina is entirely concealed by the sides of abdominal joint 9, but on 

 relaxing the specimen it is found that the entire ventral pipe is apparently 

 truncate a little before the tip of the Sth abdominal joint, leaving the 9th 

 abdominal and ventral joints in reality perfectly approximate, except at their 

 extreme tip where they, as well as the entire 10th ventral and abdominal 

 joints, are normal and exposing an enormous vulvar orifice under the tip of 

 the Sth ventral. The vulvar lamina is reduced to a very small and somewhat 

 obscure transverse, short, obsemi-oval piece, forming a prolongation of the 

 lower side of the Sth ventral, to the posterior edge of which piece is attached 

 a smaller, transverse, short, semi-oval piece, slit for its entire length. The 

 average width of the 9th ventral is about three-quarter millimetre, and the 

 anal passage is marked by a dark vitta. By this extraordinary arrangement, 

 as will be observed, almost the whole of the 9th abdominal is converted into 

 a lateral lamina, although externally no such phenomenon is apparent. Legs 

 pale brown ; femora shading into brown at their tips, especially anteriorly ; 

 tibiae and tarsi brown-black. Wings hyaline, slightly flavescent at base, espe- 

 cially the anteriors ; membranule slender and pale dusky ; veins and cross-veins, 

 including the costal, all black ; pterostigma very long, yellowish brown, sur- 

 rounded as usual by coarse black veins, surmounting 6 7 cellules, the pro- 

 longing vein of its inner side thicker than the adjoining cross veins, but a 

 very little dislocated in every wing, and also forming an angle of about 170* 



* I observe this peculiarity also in Gomphus fluvialis and anmicola mini, but not in my 

 other four species- 



[Sept. 



