56 ANGIOSPERMAE—DICOTYLEDONES 



probing for nectar dust themselves with pollen. But as at the same time they touch 

 the stigmas, automatic self-pollination necessarily takes place. According to Mac- 

 Leod, however, the anthers have lost so much of their pollen as to render this difficult. 

 Up to this time the outwardly bent styles alternate with the stamens, so that insect- 

 visits are still able to effect crossing. MacLeod states that the stamens and styles 

 ultimately become so intertangled that automatic self-pollination is inevitable. Insect 

 visitors dust their upper sides with pollen if they probe for nectar between the corolla 

 and stamens, but get covered all over with it should they creep into the base of the 

 flower between the stamens. 



The description of the method of pollination given by Schulz for the main form 



A. elongata does not entirely agree with the above account, possibly because it is 



sometimes difficult to distinguish between younger and 

 older flowers. At first the styles bend outwards so as to 

 touch the anthers, and as the flowers are homogamous 

 autogamy is thus effected. The stamens first move 

 inwards and then outwards. Towards the end of anthesis 

 the styles and stamens become closely intertangled, but 

 this does not lead to autogamy, for at this time there is 

 Fig. 2.15- Armeria, L. (from often no pollcn left, besidcs which the tips of the styles 



a photoerraph, x 4). A flower, . . , , j ..^ 



after corolla, stamens, and styles frequently projcct Irom the tangled mass. Kerner asserts, 

 have fallen off, seen from above, however, that automatic self-polliuation does take place 



Kz^ calyx-teeth; n, nve-radiate ^ 



nectary. at this Stage, Styles and stamens being thrown into 



intertwining spirals. 



Visitors. — Knuih observed the following. — 



North Frisian Is. — A. Coleoptera. i. Cantharis fusca L. (with its head in 

 the flowers). B. Diptera. All skg. or po-dvg. (a) Miiscidac : 2. Aricia lardaria 

 F. ; 3. A. vagans Fait. ; 4. Lucilia caesar Z. ; 5. Sarcophaga carnaria L. ; 6. S. sp. ; 

 7. Scatophaga stercoraria L. ; 8. Trypeta sp. ; 9. 4 sps. of smaller Muscidae. (/5) 

 Syrphtdae: 10. Eristalis intricarius Z.; 11. E. tenax Z.; 12. Helophilus pendulus Z.; 

 13. H. trivittatus F.; 14. Volucella bombylans Z. C. Hymenoptera. Apidae: 

 all skg. or po-cllg. : 15. Apis mellifica Z. ; 16. Bombus agrorum Z'. ; 17. B. distin- 

 gucndus Mor.; 18. B. lapidarius Z. ; 19. B. terrester Z. ; 20. Dasypoda plumipes 

 Pz.; 21. Panurgus ater/'z. ; 22. P. lobatus F. D. Lepidoptera. (a) Rhopalocera : 

 all skg. : 23. Argynnis aglaja Z. ; 24. Epinephele janira Z. ; 25. Lycaena semiargus 

 Roll.; 26. Pieris sp. ; 27. Satyrus semele Z. {F) Sphtngidae : 28. Ino statices Z. ; 

 29. Zygaena filipendulae Z. Helgoland. — A. Diptera. {a) Muscidae: 1. Lucilia 

 caesar Z. (h) Syrphidac: 2. Eristalis sp. ; 3. E. tenax Z. ; 4. Syritta pipiens Z. 



B. Lepidoptera. Noctuidae: 5. Plusia gamma Z. (Bot. Jaarb. Dodonaea, Ghent, 

 viii, 1896, p. 41). 



On May 6, 1897, I observed (Helgoland) the characteristic pollinator of this 

 species, i. e. Andrena carbonaria Z., skg. The proportions of the bee exactly corre- 

 spond to the dimensions of the flowers when the insect inserts its head. Also 

 (occasional), Pieris brassicae Z. J, skg., Lucilia caesar Z., do., and Scatophaga sp., do. 



The following were recorded by the observers, and for the localities stated. — 



Leege (Juist), the Noctuid moth Hydroecia nictitans Z. Verhoeff in Norderne}- 

 and Juist (J.). — A. Coleoptera. Scarabaeidae : i. Phyllopertha horticola Z., 

 po-dvg. (J.). B. Diptera. (a) Bibionidae: 2. Dilophus femoratus JZ^, ^^ skg. ; 3. 

 D. vulgaris Mg. 5 and S, skg. (IJ) Evipidae : 4. Hilara quadrivittata Mg. 5 and 5, 

 very common, skg. ic) Muscidae : 5. Aricia incana Wiedem. } and S, skg. ; 6. Cyno- 



