Hymenoptera aculeata collected in Algeria. 541 



very slight and difficult to appreciate. The males and 

 females are rarely taken together in such a way as to prove 

 their relationships, so that in separating a lot of specimens 

 into species one gets a residuum of females, whose dis- 

 tinctive characters are not strong enough to associate 

 them for certain with any particular males, and which one 

 also feels are not sufficiently well defined to describe as 

 distinct without knowing their other sex. This being the 

 case, I have been obliged to leave several apparently 

 distinct forms amongst the red-bodied females uncharacter- 

 ized, hoping that some day the discovery of their respective 

 males will enable their systematic positions to be satis- 

 factorily ascertained. 



Pompilus (Pseudopompihis) antonini, De Stef. = 

 cyanopterus, Moraw. 



$ 2, $ 1. Biskra, near railway, kilometre 199, on 



Zizyphus lotus, 3. v. 95. A. E. E. 

 J 3, ? 1. Biskra, 30. v. to 21. vi. 97. A. E. E. 

 ? 1. La Calle, 19. vii. 96. A. E. E. 



Pompilus (Ferreola) sagax, Kohl. 



$ 2. La Calle, sand-hills west of the town, 14. vii. 



96. A. E. E. 

 $ 1. Medea, wood towards Kef-el-Azeri, on Dancus 



setifolius, 2. viii. 93. A. E. E. 

 $ 1, ? 1. Biskra, 20 and 19. v. 98. F. D. M. 



Pompilus (Planiceps) castor, Kohl. 



$ 1, ? 1. Algiers, 21. iv., 4. iv. 98. F. D. M. 

 $. Constantine, 17. vi. 98. F. D. M. 



Pompilus (Planiceps) hirtipennis, n. sp. 



^ Niger capite et thorace pnbescentibus, aureofnscis sub-micanti- 

 bus, prothorace meso et metathoraci propodeoque simul sumptis 

 longitudine fere sequale. Alis obscuris, subbrevibus dense pilosis, 

 coxis femoribusque anticis valde dilatatis tarsis brevibus pectine 

 nullo, abdomine pube griseo-fusca subconspicna tecto. 



9 Black, head and thorax densely clothed with a close golden- 

 brown shining pile, antennae and mandibles piceous, head shaped 



