1^8 J^S YCHE [ A ugust 



that of other members of the genus in general characters as stated in the above 

 cited Bulletin. Its more distinctive characters are the following: — 



Length ii mm., gills 4 mm. additional. Gills plainly colored, a little darker along the 

 axis, but without spots or bands. Mental setae of labium four each side in an equal uniform 

 series ; lateral setae 5. On the end of the lateral lobe above the end hook are three distinct 

 teeth, and the obliquely truncated outer angle is obscurely denticulate. 



Two pairs of IscJuiura damula Calvert (recently described in Biol. Centr. 

 Anier., $ only) were taken at Arroyo Pecos on June 7 along with the above 

 described forms. Both females are old and pruinose blue. They measure in total 

 length 27 mm., abdomen 20 mm., hind wing 15 mm. There is no ventral spine 

 on the 8th abdominal segment. The stigma is distinctly smaller (smaller by about 

 one third) in the hind wing than in the fore. The hind margin of the prothorax is 

 slightly concave on either side of the dorsum, produced backward in the middle and 

 divided there by a minute median notch. The nasus is metallic green, but the top 

 of the head and thorax, the upper surfaces of the femora, and the whole dorsum of 

 the abdomen (save for invading streaks of yellowish on the sides of the 2d seg- 

 ment) are blackish pruinose. 



(C.) Dimmitt Lake, ?iear Roswe/L 



On the east side of the Pecos River, near Roswell, is a line of red bluffs 

 consisting of impure gypsum. At the foot of these bluffs is a series of small lakes, 

 which are so deep as to be popularly reputed "bottomless." These lakes are so 

 strongly impregnated with salts that the water is hardly suitable for drinking pur- 

 poses. Along their margins dragon-fly nymphs may be found, and dragon-flies 

 (•mostly libellulines) were observed to be very numerous. 



The identification of the species of Dytheinis is more or less uncertain. 

 Captain Pope collected on the Pecos River D. velox Hag., D. fugax Hag., and 

 D. mendax Hag. Dythemis (now Brechmorhoga) mendax may be eliminated 

 because its venation does not agree with that of the nymphal wings : as between 

 £). velox and D. fiigax, judging by size alone, the nymphs should belong to the 

 latter, rather larger species, but the former only was collected at the same time 

 and place. 



In Proc. Davenport Acad. Sci. vol. 9 (1902), p. 51, it is inferred that Pope 

 collected his material at very different localities above the river, since he obtained 

 both Mela7ioplus bivittatus and M. differentials, which inhabit different life-zones. 

 However, in 1902 it was observed that these two grasshoppers do actually occur 

 together at Roswell. As it is not very likely that their ranges overlap very much, 



