206 Annals of the Carnegie Museum. 



Habitat : — Peru, Puno, November 1-3, 1898, by Wm. J. Gerhard, 

 14 rj*, 2 homoeochromatic 9, 14 heterochromatic 9. Academy of 

 Natural Sciences of Philadelphia. 



Puno, by Garman, 1 $. Museum of Comparative Zoology, Cam- 

 bridge, Mass. 



Bolivia, Chililaya, November 5, 1898, by Wm. J. Gerhard, 8 d\ 1 

 homoeochromatic 9 > 8 heterochromatic $ . Academy of Natural 

 Sciences of Philadelphia. 



Both of these localities are on Lake Titicaca and therefore at an ele- 

 vation of 12,500 feet 26 (371 1 metres) above the sea, one of the highest 

 altitudes from which Odonata have as yet been reported. 



This is the first species of Amphiagrion known from South America. 

 It resembles the type of the genus A. saucium (Burm. ) of North Amer- 

 ica, not only by positive characters set forth in the most recent limi- 

 tation of the genus, 27 but also in the variability of the point of origin of 

 M 2 (= nodal sector of de Selys) on the hind wings. Ten males, ten 

 females of A. titicacce from Puno have this origin at the fourth post- 

 nodal in 55 per cent. cT, 45 per cent. $; at the third in 35 per cent. 

 J\ 50 per cent. 9; and mid-way between third and fourth in 10 per 

 cent. cT, 5 per cent. 9. 28 



A. titicaca differs from A. saucium by its less oblique pterostigma, 

 the presence of blue on the posterior abdominal segments, the shape 

 of the abdominal appendages of the male, etc. 



108. Ischnura ? nepos Selys. 



(Plate VI, figs. 121, 122.) 

 Agrion? nepos (Bates Mss. ) Selys, Bull. Acad. Belg. (2) xli, p. 1249. 1876. 



9 (hitherto unknown); (homoeochromatic). Differs from de 

 Selys' description of the male as follows : Pterostigma ochre \ blue 

 postocular spots circular; black on the dorsum of abdominal segment 

 9 divided into two separate or confluent spots, reaching from base to 

 mid-length of the segment ; dorsal surface of 10 (which is pale in some) 

 almost carinate medially ; appendages shorter than 10, straight, simple, 

 pale or dark ; 8 with a well developed vulvar spine ; genital valves 



2G Intercontinental Railway Commission quoted by Gannett, Bull. Internat. Bureau 

 Amer. Republ. Sept. 1904, p. 51. 



27 Calvert, Biol. Centr.-Amer. Neurop. p. 102. 1902. 



28 Compare Calvert, /. c, p. 102, footnote f. 



