696 PROCEEDINGS OF THE NATIONAL MUSEUM. vou xxvii. 



Museum Accession No. 2666^. These are quite the most distinctly 

 marked species of the genus that I have seen. 



The largest measures in total length 32 nun., abdomen 21 mm., hind 

 femur 6 mm. ; width of head 7 nnn., of abdomen 7.5 mm. The hinge of 

 the labium (Plate XLIII, tig. 6) reaches backward barely as far as 

 the metathorax. The median lobe is very short, and its middle cleft 

 is tightly closed all its length. The end of the lateral lobe is squarely 

 truncate, and not narrowed to the tip, and lacks end hook. The upper 

 line of the superior appendage of the alxlomen is straight — not convex 

 in the least — and the laterals are three-fourths to four-tifths as long as 

 the superior. 



Lateral spines are obsolete on the sixth a))dominal segment, and 

 small on the seventh, ])ut well developed upon the eighth and ninth, 

 thus exhibiting a development that has hitherto been considered as 

 distinctively characteristic of Ana.r. ^Ir. Currie pointed out in the 

 original description of this species" that it is closely allied* to ^. cali- 

 fornk-iU and in my description of the nymph of that species* I have 

 mentioned the squareh' truncated lateral lalnal lobes, correlated with 

 less development of the lateral spines of the abdominal segments than is 

 shown by nymphs of the more tvpical species of ^Eselina. 



Siah)fa«aily CORr)TlTLP:C+.A.STKRI]Sr^E. 



CORDULEGASTER DORSALIS Selys ? 



Plate XXXIX, fig. 3. 



"Upper Firehole Basin, Yellowstone Park, 1872, C. H. Merriam." 



Length, 35 mm.; alVdomen, 23 mm.; hind femur, 7.5 mm.; width 

 of head, 8.5 mm.; of abdomen, 8.5 mm. 



Blackish, clothed with tawu}- hair only on sides of thorax, legs, and 

 apical carin^e of alidominal segments. Head narrowed behind the 

 ej'Cs, hardl}^ concave posteriorly. Labium broad; median lobe with 

 the usual bifid middle tooth (fig. IZ*), the divisions of which are truncate 

 on the end, with a very shallow indentation on the side, followed by a 

 straight row of five or six excessivel}" minute denticles and the usual 

 fringe of hairs. Lateral seta?, 6-7; mental setse, 8-9 each side, the 

 outer five in a separate, stronger series and closer together; teeth as 

 usual. 



Wing cases reaching to the middle of the fifth abdominal segment. 



Abdomen regularly tapering to a sharp point; no dorsal hooks; no 

 lateral spines; appendages decurved at apex, as long as the ninth and 

 tenth segments together; lateral appendages one-fourth as long as the 

 others. 



«Pn c. Washington Acad. Sci., Ill, 1901, p. 385. 

 ''Bull. 111. State Lab. Nat. Hist., VI, p. 45. 



