10 ODONATA. 



tip a rudimentary 4th joint, only to be seen when much magnified. 

 Vertex flat, ocelli visible. Occiput short, hind-border notched ; median 

 line impressed, on each side a small conical tubercle ; lateral hind- 

 angles elevated, pyramidal. Mask square, somewhat produced at fore- 

 border. Palpi small, not denticulated, blunt; hook sharp, longer than 

 the palpus. Prothorax narrow, excavated, hind border a little rounded ; 

 a transverse impression near fore-border. Legs formed for running, 

 flat, slender. The fore and middle legs short; the fore legs shortesl ; 

 femora flattened, edged with white hairs ; tibiae angular, longer than 

 femora ; tarsi half as long as tibia), 2-jointed, basal joint very short. 

 Hind legs long, femora reaching nearly to 7th segment; tibia? of equal 

 length to femora, tarsi 3-jointed, basal short, 2d longer, 3d equal to both 

 in length. Wing-cases reaching 6th segment. Abdomen lancet-shaped, 

 exceedingly flat, broader than head, nearly circular, dorsum some- 

 what elevated. Segments of nearly equal length, excepting 10th, 

 which is very small and inserted in 9th. Segments 5 to 6 broadest, the 

 others decreasing, the 9th nearly triangular. The outer edges of seg- 

 ments 2 to 8 form border, sharp and pointed at hind angles. Dorsal 

 hooks prominent, flattened laterally and bent backward, less prominent 

 on 7th to 9th segments. Anal appendices short, stout, pyramidal, 

 blunt, a little longer than 10th segment. Superior somewhat shorter, 

 channelled at sides, lateral very small, half as long as the others. The 

 8th ventral segment has small bifid vulva lobe. 



13. Hagenius (Sieboldius) japonicus. 



Selys, Monogr. des Gompli., p. 244, No. 87. 



Plate III., fig. 5, c. 



Locality : Kanagawa, Japan. Coll. Mus. Comp. Zool. One nympha, 

 male, not full grown. Length, 28 mm. 



Very similar to H. brevistylus, differs as follows : Head a little shorter ; 

 hind end of the part between antennae less deeply notched ; inserted 

 tubercle rounded ; 3d joint of antenna? not so rounded. Hind angles 

 of occiput blunt. Abdomen straighter at sides, 9th segment shorter ; 

 lateral angles of 9th not so sharp. Dorsal hooks modified in flattened 

 tubercles. Anal appendices sharper, superior bluntest, not so deeply 

 channelled at sides ; the tip seems to be broken, before the tip are 

 three rounded tubercles; perhaps this is a sexual character; wing-cases 

 reaching to middle of 3d segment only. As a species Hagenius japonicus 

 is found in Japan, this nympha is supposed to be the incomplete 

 insect. 



