ioo ANGIOSPERMAEDICOTYLEDONES 



Z., very freq. ; 7. Scatophaga stercoraria Z. 5 and $, very freq.; 8. medium-sized 

 Muscids. (b) Syrphidae: 9. Eristalis arbustorum Z. o. and $, very freq.; 10. E. 

 tenax Z. $ and S, freq,; n. Helophilus trivittatus F. 5, occasional; 12. Syritta 

 pipiens Z., very freq. B. Hymenoptera. Apidae: 13. Andrena carbonaria Z. J, 

 2nd brood. C. Lepidoptera. Rhopalocera : 14. Pieris brassicae Z., occasional. 

 D. Orthoptera. 15. Forficula auricularia Z., very freq., dvg. the flowers. All 

 these insects were observed from July 8 to 11, 1895, on the high ground. 



Verhoeff noticed the following in Baltrum. A. Coleoptera. (a) Nitidulidae : 

 1. Meligethes brassicae Scop. (b) Scarabaeidae \ 2. Phyllopertha horticola Z. 

 B. Diptera. Muscidae : 3. Anthomyia sp. 



Heinsius saw a Muscid Scatophaga stercoraria Z. $, and a hover-fly Eristalis 

 arbustorum Z. 5 in Holland (Bot. Jaarb. Dodonaea, Ghent, iv, 1892). 



H. de Vries noticed a humble-bee Bombus subterraneus Z. 5 in the Nether- 

 lands (Ned. Kruidk. Arch., Nijmegen, v, 1877). 



233. B. fruticulosa Cyril. This species is self-fertile (Comes, ' Stud. s. impoll. i. 

 ale. piante'). 



66. Sinapis Tourn. 



Flowers yellow, homogamous or slightly protogynous. In some species the 

 sepals project horizontally, so that the nectar is exposed, but in others it is 

 completely concealed. Four nectaries, situated as in Brassica. 



234. S. arvensis L. (Herm. Muller, ' Fertilisation,' p. 112, ' Weit. Beob.' II, 

 pp. 204-5; Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins./ pp. 28, 149, 'Blutenbiol. Beob. 

 a. d. Ins. Riigen'; Kirchner, 'Flora v. Stuttgart/ pp. 299, 300.) As the sepals are 

 horizontal the nectaries are visible and accessible from the exterior, but the flowers 

 are so crowded that insect visitors find it more convenient to thrust the proboscis 

 between the stamens to the nectar, and this is their regular practice. The anthers of 

 the long stamens at first turn their dehisced sides towards the adjacent short stamens, 

 but on the third day of flowering direct them upwards, while the filaments curve 

 downwards, so that if the pollen has not been removed by visitors and pollination 

 effected, the stigma, by pushing up between the anthers, will be automatically pollinated. 

 Eggers observed according to Hansgirg pseudo-cleistogamy. Jordan says that, as 

 a rule, only the two nectaries opposite the short stamens are functional. According 

 to Kerner the flowers are protogynous. Warnstorf (Verh. bot. Ver., Berlin, xxxvii, 

 1895) describes the pollen-grains as yellow, ellipsoidal, with delicate regular ridges 

 which cross one another. 



Visitors. Herman Muller (H. M.), Buddeberg (Budd.), and myself (Kn.) have 

 observed the following. 



A. Coleoptera. (a) Alleculidae : 1. Gonodera murinaZ. (H. M.). (b) Ceram- 

 bycidae: 2. Leptura livida F., dvg. the anthers (H. M.); 3. Strangalia nigra Z., ditto 

 (H. M.). (c) Coccinellidae'. 4. Coccinella septempunctata Z., nect.-lkg. (H. M.). 

 (d) Nitidulidae : 5. Meligethes sp., freq. (H. M., Kn.). (e) Scarabaeidae : 6. Phyllo- 

 pertha horticola Z, gnawing the flower (H. M.). B. Diptera. (a) Conopidae : 

 7. Dalmannia punctata F., skg. (H. M.). 8. Myopa buccata Z., skg. (H. M.). 

 (b) Empidae: 9. Empis sp., skg. (H. M.). (c) Muscidae: 10. Lucilia sp., po-dvg. 

 (H. M.); 11. Scatophaga merdaria F. (H. M.). 12. S. stercoraria Z, po-dvg. 

 (H. M.). (d) Syrphidae: 13. Chrysogaster macquarti Loezv, po-dvg. (H. M.); 

 14. Eristalis aeneus Scop., skg. and po-dvg. (H. M.); 15. E. arbustorum Z., freq., 



