THE CANADIAN ENTOMOLOGIST. 255 



Head compact, one-lhird wider than long, scurfy, hairy above 

 excepting a pair of bare spots near the hind margin, with prominent 

 hemispherical eyes covering the antero-lateral angles, narrower behind 

 the eyes, with parallel sides, rounded hind angles, and almost straight 

 hind margin. Antennae shorter than the head is long, 7-jointed, with 

 scattering hairs along the distal joints. Labium extending posteriorly 

 between the bases of the fore legs; median lobe broadly triangular, half 

 as long as wide, rounded on tip, with two spinules close together just 

 before the tip, and several others each side along the front border farther 

 apart ; raptorial setre on the mentum, 10 each side, the fourth or fifth 

 (counting from the side) longest, the three innermost ones quite small ; 

 lateral labial lobes ample, with six raptorial setae, and a spinule at the 

 base ; hook straightish to the slender, slightly-incurved tip, hardly longer 

 than the setae, but much stouter; teeth almost obsolete, bi-spinulose. 



Prothorax with prominent spiracles ; legs hairy, especially the tibiae 

 externally ; tarsal claws not strongly incurved ; second tarsal joint one- 

 half longer than the first, and the third one-half longer than the second ; 

 wings reaching well upon the 6th abdominal segment. 



Abdomen somewhat depressed, oblong, widest on the 6th segment, 

 the 9th segment as wide as the 2nd, narrowed with extraordinary abrupt- 

 ness on the 10th segment, which is almost included within the apex of 

 the 9th. No dorsal hooks at all ; in their places are tufts of a few long 

 hairs, and whitish spots in the anteapical membrane of the segments. 

 Lateral spines on segments 8 and 9, hooklike, starting outward at base, 

 and incurved at tip, on 8 one-half the length of the segment, on 9 a little 

 longer than on 8. Hairs on the apical carinse well developed, especially 

 so on segment 9, which they completely encircle, constituting a long 

 fringe which completely overhangs the 10th segment and the appendages. 

 Appendages about as long as the 9th segment is on its slightly shorter 

 dorsal side, lateral appendages a third shorter. 



Since the discovery and description of the nymph of Tachopteryx 

 Thoreyi, Sel., by Messrs. Atkinson and Williamson, last year, this species 

 has remained the most important discovery to be made. It is our only 

 representative of that singular group of Libelluline genera which Karsch 

 called the Nannophyae*. Mr. Weith's zeal and industry have brought this 

 nymph to light, and there now remain of all the genera of Odonata of the 

 northern United States and Canada but two in which no nymphs are 

 known, and they are Gomphceschna and Micrathyria. 



*Ent. Nachr., vol. xv. , pp. 245-263. 



