18!I7.] 153 



Sub-fam. LIBELLULIN^. 

 Stmpeteum Ponscolombii, Selys. — Medea, July 5th, 1893, and 

 Biskra, May 26th, 1894. 



Stmpeteum steiolatum, Charp. — A few examples from Con- 

 stantine in June and October, 1894, and October, 1895. 



Stmpeteum meeidionale, Selys. — A few examples, Bone, June 

 4th, 1896 ; Lac des Oiseaux, June 18th and 25th, 1896. 



Stmpeteum sanguineum, Miill. — Ain Kriar, June 22nd, 1896. 



Teithemis eubeineevis, Selys. — Lac Tonga, June 24th and July 

 13th and 16th, 1896; Lac Houbeira, June 11th, 1896. I have never 

 seen European (typical) examples of this species. Do Selys remarks 

 that Algerian examples are larger than those from West Africa. I 

 am quite of the same opinion, and they also seem more robust, with a 

 larger pterostigma, &c. I find no apparent differences in the genita- 

 lia of the second segmeut. 



Ceocothemis eetthejea, Brulle. — A few individuals, varying 

 much in size and intensity of colour, from Biskra, Bone, La Calle and 

 Lac Tonga at varying dates. One example from Biskra is ticketted 

 " January 9th, 1895," but I suspect an error on my part. 



Caceegates leucosticta, Burm. — About a dozen examples from 

 Lac Tonga, Lac Houbeira and Lac des Oiseaux in June and July, 

 1896. Mr. Eaton remarks that the species is gregarious in habit. The 

 females have the wings entirely hyaline. 



N.B. — De Selys (Ann. Soc. Ent. Belg., xxxi, p. 23), possibly copying from 

 Brauer (Verhandl. z.-b. Gcsell. Wien, xviii, p. V36), used the specific name " uni- 

 fasciata, Oliv.," for this insect. There is no such name in the Encyc. Method., 

 and I know not where else to look for it. Rambur's unifasciata is the same species, 

 but his name was original. 



Oetheteum teinaceia, Selys. — Lac Tonga, Lac Houbeira and 

 La Calle in July, 1896, seven examples. 



N.B. — This species was placed in Lepthemis by Brauer ; latterly it has been 

 located in Orthetrum, which is nearer its proper position. But it (and others) will 

 probably be found hereafter in a new genus, differing from Orthetrum typically in 

 having the sectors of the triangle in the posterior wings distant at their origin. 



Calvert (Proc. U. S. Nat. Mus., xviii, p. 127) calls attention to the fact that 

 Karsch (Ent. Nachr., xvii, p. 59) differentiates Orthetrum by {inter alia) its 

 having the above-mentioned sectors separated at their origin, but in error, for in 

 typical Orthetrum (Newman) such a condition only occurs accidentally. In examin- 

 ing a very large number of specimens of European species, I find this condition to 

 exist in only about one per cent. 



In Lib. Sabina, Drury, which used also to be placed in Lepthemis, but now in 

 Orthetrum, in all examples from Asia (therefore typical) and Polynesia these sectors 



