EEY. A. E. EATON OX EECEXT EPHEilEEID-E OE MATELTES. 263 



shortly and acuminately produced into teeth at the hinder angles of segments 7-9. 

 Fangs of the mandihles slim, compressed and subeqal in length ; the exterior tridenti- 

 culate at the summit, and serrulate along the superior edge ; the interior fangs diversi- 

 form, terminated each by a tooth and two denticulations ; in the right mandible the tooth 

 is intermediate between the denticulations, is subulate, elongate, and slightly twisted, 

 and the inferior denticulation is preceded by a few short hairs placed in a row along the 

 edge of the fang ; in the left mandible the tooth is somewhat conical and is above the 

 denticulations. Lacinia of maxilla i. beset at the edge of the crown with short appressed 

 triangular pectinate teeth, and terminated by two simple pungent spinules ; proximal 

 joint of the palpus stout; terminal joint comparatively slender, its inner side nearly 

 straight, the outer side gently curved, pungent at the point and somewhat pilose in 

 proximity to its termination externally. Median lobe of the tongue inflated, subovate, 

 grooved lengthwise in the middle nearly as far as the tip, and then transversely tumes- 

 cent ; paraglossae broadly dUated, slightly recurved at the tips, and much larger than 

 the median lobe. Femora, on the coloured side, banded with grey in two or three 

 places ; the bands confluent below. Length of body 7 ; setae about 7 mm. 



Sab. Xiagara and Trenton Falls, X. T. (G. H. Hubbard, 20 & 22, v. 1874) ; Dakota 

 (Cones, 1872 & 1873), common; also X. Illinois (Prof. T^'. A. Forbes, vi. 1883). 

 Figured and described from sj^ecimens communicated by Dr. Hagen (in Mus. Comp. 

 Zool. Cambridge, Mass.). 



It is possible that the Swedish insect figured by De Geer, Mem. pour servir a I'Hist. 

 des Ins. ii. part ii. pi. xviii. 1—4, may be congeneric with Xymph Xo. I. The nymph 

 was found by him in May in a ditch by the gardens of Leufsta, near Dannemora, in 

 which grew many species of aquatic plants. Towards the end of May the imago appears, 

 of which the oculi are sea-green. The nymphs climb uj) the plants to undergo the 

 penultimate moult. 



XriiPH Xo. II. — PI. LVIII. (whole figure and details). 



Six anterior pairs of the abdominal tracheal branchiaj provided with broad, obtuse or 

 refuse laminfe recumbent upon the sides of the dorsum; laminae of the seventh pair 

 linear-lanceolate and spreading. The anterior laminae are quadrilateral, longer than 

 broad, oblique at ths base, pilose at their exposed edges, and pergamentose ; all but the 

 foremost are auricled at the base on the lower side, and all are slightly sinuate at the 

 base on the upper side, the foremost being merely dilated instead of auricled corre- 

 spondingly ; distally the first three are truncate and slighly refuse, but the next three 

 are obtusely rounded at the extremities ; the hindermost lamina;, linear-lanceolate, 

 acuminate and ciliated, lie outwards and obliquely backwards from the sides, and 

 seemingly are destitute of branchial fibrils. Each of the anterior laminae contains a 

 strongly defined fruticosely branched trachea, and partially overlies the explanate 

 branchial fibrils which are connected together by membrane as in Xymph Xo. I., but 

 more extensively and so as to resemble an oval membranous lamella, deeply fringed 

 *vith branched filaments, and produced into a laciniated auricle at the base on the 



35* 



