1903] A'EEDHAM, COCKERELL: — NYMPHS OF ODOXATA 130 



it thus seems likely that Pope's collections, if all from one place, were from the 

 vicinity of the present town of Roswell, rather than from Lat. 32° (the present 

 boundary between New Mexico and Texas), as Hagen indicates. In all probabil- 

 ity, however, the collections were made in several places. 



The following species of Odonata were collected at the same place and time 

 as the nymphs described below : Dythemis velox Hagen, Libelliila odiosa Hagen, 

 Plathemis suboniata Hagen, Mesothemis collacata Hagen, Enallagma civile Hagen, 

 E. basidens Calvert, Hetaeritia americana Beauv., and a single undeterminable 

 female of a species of Argia. Of these, the first five agree perfectly with the 

 descriptions of the types, sent originally by Captain Pope from this same locality. 



Dythemis sp.? 



Four cast nymphal skins collected at Dimmitt Lake near Roswell, N, Mex., in 

 August, 1902. These constitute a valuable discovery, since no nymphs of this 

 genus or any of its immediate neighbors in the system have been made known 

 hitherto. The generic determination is possible because the venation of the adult 

 is well marked in many important particulars upon the empty wing sheaths. 



Length 20 mm., abdomen 12 mm., hind femur 6 mm., width of head 6 mm., of abdomen 



7 mm. 



Body stout, nearly smooth, depressed. Head widest behind the middle across the 

 rear of the broad eyes, abruptly sloping behind the eyes to the nearly straight, scurfy 

 pubescent hind margin. Antennae slender hardlj- as long as the head, sparsely hairy toward 

 the tip. Eyes directed antero-laterally. Labium wide, thin; hinge reaching posteriorly as 

 far as the mesothorax. Mentum with a very prominent and broad median lobe whose mar- 

 gin is entire and nearly bare. Mental setae about 12 each side, the outer seven stronger. 

 Lateral lobes broad, lateral setae 10, with a very minute axial seta or spinule at base. Teeth 

 on opposed margins of lateral lobes nearly obsolete, but armed with about four graduated 

 spinules each ; at the inner angle are a number of scattered stronger marginal spinules. 

 Movable hook slender and setiform, nearly straight to the incurved tip. 



Legs slender, thinly hairy externally. Wing cases reaching posteriorly to the apex of 

 the 6th abdominal segment. 



Abdomen triquetral, with sharp lateral margins, the sides nearly parallel except at the 

 ends, abruptly truncated in the rear, hardly narrowed before the 9th segment. Lateral 

 spines on segments S and 9, straight and sharp, with finely spinuiose external margins, on 



8 half as long as the segment, on 9 full as long as the segment. Dorsal hooks on segments 

 3-9, slender and straight and strongly directed posteriorly, longest on segment 7, where as 

 long as that segment, diminishing in length toward both front and rear : loth segment short 

 and included in the apex of the 9th. Appendages triquetral, hardly surpassing the level of 

 the tips of the spines of the 9th segment; superior and inferiors equal, the laterals hardlv 

 more than half as long. 



