1897.] 155 



In the ^ there arc 10-13 antcnodals and 6-7 postnodals in the anterior wings. 

 The size varies as follows: — posterior wing 21-27 mm., abdomen (cum append.) 

 30-34i mm. ; the examples from Constantino are larger than those fi'om Biskra. 



? (not hitherto described). Generally as in tlie (? (the bands of the thorax 

 wholly wanting in one individnal). Occiput hardly differing from that of the ^. 

 The blackish articulations of the segments of the abdomen, and false sutures, less 

 marked than in the J . Margins of the 8th segment only slightly dilated laterally. 

 Appendages longer than the 10th segment, yellow, straight, lanceolate, very acute ; 

 between them is a shorter, conical, yellow process. Vulvar scale yellow, small and 

 short, deeply notched in the middle, the sides forming short cones. 9-11 antenodals 

 and 7-9 postnodals in anterior wings. Length of posterior wing, 27 mm. ; abdomen, 

 33 mm. (both examples are from Constantine). 



Ontchogomphus Genei, Selys. — Three (^ and two $ from Biskra 

 in April, May and June, and ^ and ? from Lac Houbeira. At first 

 I was disposed to consider the examples from the separate localities 

 represented two distinct species, those from Biskra having the abdo- 

 iKen less darkly marked, and there is no dark hand on the top of the 

 front before the ocelli ; to these I was inclined to apply the name Genei 

 (as represented by the original type from Sicily), and this opinion was 

 strengthened by the fact that one ? has the small black teeth on either 

 side of the edge of the occiput as mentioned for the type (Mon. 

 Gomph., p. 52), but these teeth are absent in the other $ from the 

 same locality, which otherwise is similar. The examples from Lac 

 Houbeira I inclined to consider 0. Hagenii, Selys (with excelsus, Costa, 

 as a sononym). In these the abdomen is somewhat heavily marked 

 "with black, there is a hroad blackish ba?id at the top of the front before 

 the ocelli (no trace of teeth on the edge of the occiput in the $ ), and 

 the characters generally are as in Costa's types of O. excelsus (from 

 the island of Sardinia), from which O. Hagenii (type from Abyssinia) 

 seems to differ only in the abdomen being still more blackish at the 

 extremity. Also it is possible that the inferior appendage (seen from 

 beneath) is rather more dilated at its extremity in these latter 

 examples. 



In all the foregoing the superior appendages are truncate and 

 slightly excised* at the tips if viewed from beneath. 



N.B.- — The Upper Egyptian and Nubian 0. pumilio, Rb., is distinct ; apart 

 from its small size and pale colour, the tips of the superior appendages are entire or 

 acute, the inferior appendage sliglitly different, and there is a marked difference in 

 the form of the anterior lobe in the genitalia of the second segment. 



I think it will eventually be proved that Genei, excelsus and Hagenii are local 

 races of one species ; that excelsus is more allied to Hagenii than to Genei ; and 

 that both Genei and excelsus (as races) occur in Algeria. 



* Not /fplit a.s is represented in Hagen's figure (Mon. Gomph., pi. 3, fig. ie). 



