CRUCIFERAE 79 



nectar. Schletterer records the following list of visitors noticed in the Tyrol (T.), 

 and at Pola. 



Hymenoptera. (a) Apidae: 1. Andrena albicrus K. <j> and J (T.); 2. A. 

 albopunctata Rossi=A. funebris Pz. ; 3. A. caibonaria Z.; 4. A. flavipes Pz.) 5. 

 A. morio BrulL; 6. A. schlettereri Friese; 7. Bombus argillaceus &cop., skg.; 



8. Eucera longicornis Z.; 9. Halictus calceatus Scop. ; 10. H. levigatus K. 5 ; 11. H. 

 morio F. ; 12. H. scabiosae Rossi; 13. H. villosulus K. ; 14. Podalirius acervorum 

 Z. ; 15. P. crinipes Sm. ; 16. P. nigrocinctus Lep. ; 17. P. retusus Z. var. meridionalis 

 Per. ; 18. Xylocopa violacea Z. (b) fchneumonidae: 19. Bassus laetatorius F.; 20. 

 Homotropus tarsatorius Pz. The short-tongued bees were undoubtedly only po-cltg. 



51. Nasturtium R. Br. 



White or yellow homogamous flowers, with half-concealed nectar. Nectaries 

 four or six. 



173. N. officinale R. Br. (Herm. Miiller, ' Weit. Beob.,' p. 325, ' Alpenblumen,' 

 p. 153; Kirchner, 'Flora v. Stuttgart,' p. 286; Knuth, 'Bl. u. Insekt. a. d. nordfr. 

 Ins.,' pp. 24, 148.) Flowers white. There are two green fleshy nectaries placed 

 close together on the inner side of the base of each short stamen. The short 

 stamens turn their pollen-covered sides towards the stigma, which projects far beyond 

 them. The four long stamens at first reach the level of the stigma, but later on 

 this is higher. They are so turned towards the short stamens that the head or 

 proboscis of an insect probing for nectar must simultaneously touch the stigma 

 and the pollen-covered sides of the three nearest anthers. In rainy weather the 

 flowers remain almost closed, so that automatic self-pollination is effected by the 

 pollen of the long stamens. Warnstorf (Verh. bot. Ver., Berlin, xxxviii, 1896) says 

 that the flowers are slightly protogynous ; that the longer stamens reach the level 

 of the stigma; and that after the pollen is shed the filaments and anther-lobes 

 become violet in colour. 



Visitors. The following were observed by myself (Kn.) on the island of 

 Fohr, and by Hermann Miiller (H. M.) in Thuringia. 



A. Coleoptera. Nitidulidae : 1. Meligethes (H. M.). B. Diptera. (a) Cono- 

 pidae: 2. Physocephala rufipes F., occasional, skg. (H. M.). (b) Empidae: 3. Empis 

 livida Z., very freq., skg. (H. M.) ; 4. E. rustica Fallen, ditto (H. M.). (c) Muscidae : 

 5. Ocyptera cylindrica F., skg. (H. M.). (d) Syrphidae : 6. Eristalis arbustorum Z., 

 freq., skg. (H. M.); 7. E. nemorum Z., ditto; 8. E. sepulcralis Z., ditto (H. M.) ; 



9. E. sp., ditto (H. M.) ; 10. Helophilus floreus Z., in large numbers, skg. and 

 po-dvg. (H. M.); 11. Melithreptus sp., po-dvg. (H. M.); 12. Syritta pipiens Z. (Kn.), 

 and 13. Syrphus sp. (Kn.), both skg. C. Hymenoptera. Apidae: 14. Apis mellifica 

 Z. 5, skg. (H. M., Kn.); 15. Halictus maculatus Sm. jjf, skg. andpo-dvg. (H.M.). 



Hermann Miiller also observed in the Alps 2 Hymenoptera and 4 Diptera ; 

 while MacLeod noticed in Flanders Apis, and an Eristalis (Bot. Jaarb. Dodonaea, 

 Ghent, vi, 1894, p. 196). 



In Dumfriesshire (Scott- Elliot, 'Flora of Dumfriesshire,' p. 11) beetles and 

 numerous flies were observed. 



174. N. amphibium R. Br. (Herm. Miiller, 'Fertilisation,' p. 102, 'Weit. 

 Beob./ i, p. 324 ; Kirchner, 'Flora v. Stuttgart,' p. 287; Knuth, 'Bl. u. Insekt. a. d. 

 nordfr. Ins.,' p. 24.) Flowers yellow. The six nectaries are placed in the intervals 



