126 ANGIOSPERMAEDICOTYLEDONES 



A certain intermediate number of beetles will therefore be of use to the plant, 

 and this mean will always be maintained for the mutual benefit of plant and insect 

 (cf. vol. I, p. 102). 



In Dumfriesshire 2 Muscidae and also Meligethes have been observed (Scott- 

 Elliot, 'Flora of Dumfriesshire,' p. 19). 



311. C. tatarica Wulf. According to Kerner's researches artificial self- 

 pollination is ineffective. 



312. C. pinnatifida R. Br. 



Visitors. Loew observed the following in the Berlin Botanic Garden, all skg. 

 A. Diptera. Syrphidae: 1. Eristalis arbustorum Z. ; 2. Syritta pipiens Z.; 



3. Syrphus ribesii Z. B. Hymenoptera. Apidae : 4. Apis mellifica Z. 



313. C. grandiflora DC. 



Visitors. Loew observed a hover-fly (Melithreptus scriptus Z., skg.) in the 

 Berlin Botanic Garden. 



IOO. Raphanus Tourn. 

 Whitish, homogamous flowers, with half-concealed nectar. Four nectaries. 



314. R. Raphanistrum L. (Herm. Miiller, 'Fertilisation,' p. 113,' Weit. Beob.,' 

 II, p. 205; MacLeod, Bot. Jaarb. Dodonaea, Ghent, vi, 1894, p. 208; Kirchner, 

 'Flora v. Stuttgart,' p. 302; Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 32, 140, 

 'Bl. u. Insekt. a. d. Ins. Rvigen'; Warnstorf, Verh. bot. Ver., Berlin, xxxvii, 1895.) 

 The nectaries are situated as in Sinapis arvensis, but owing to the erect position 

 of the sepals their secretion is not visible and easily accessible from without. The 

 petals are either white with violet veins, or bright yellow with dark yellow veins. 

 All the anthers turn their dehisced sides towards the stigma, beyond which the 

 long stamens project, while those of the short ones are at the same level. Automatic 

 self-pollination therefore appears to be even more favoured than in Sinapis, but 

 it is ineffective. Warnstorf describes the pollen-grains as being pale yellow in 

 colour, ellipsoidal, very finely reticulated and tuberculated, about 37-5 p long and 

 31 ix broad. 



Visitors. Hermann Miiller (H. M.) in Westphalia, myself (Kn.) in Schleswig- 

 Holstein, have observed the following. 



A. Coleoptera. Nitidulidae : 1. Meligethes brassicae .SV-0/>. (Kn.). B. Diptera. 

 Syrphidae : 2. Melanostoma gracilis Mg., skg. (Kn.) ; 3. Rhingia rostrata Z., freq., 

 skg. and po-dvg. (H. M.); 4. Syritta pipiens Z., po-dvg. (H. M., Kn.); 5. Syrphus 

 ribesii Z., po-dvg. (H.M.); 6. S. sp. (Kn.). C. Hymenoptera. {a) Apidae: 7. Apis 

 mellifica Z. $j, skg. and po-cltg. (H.M., Kn.); 8. Bombus lapidarius Z., skg. (Kn.); 9. 

 B. muscorum F. 5, skg. (H. M.); 10. B. pratorum Z., skg. (Kn.); n. B. variabilis 

 Schmied. 5, skg. (H. M.); 12. Halictus fiavipes F. 5, skg. (H. M.); 13. H. smeath- 

 manellus K. 5, skg. (H. M.). (b) Tenthredinidae : 14. Cephus pygmaeus Pz. (H. M.). 

 D. Lepidoptera. Rhopalocera: 15. Coenonympha pamphilus Z. (H. M.); 16. Rho- 

 docera rhamni Z. (Kn.); 17. Lycaena sp. (Kn.); 18. Pieris napi Z. (Kn.), and 19. 

 P. rapae Z. (Kn.) ; all skg. 



Alfken noticed the bee Halictus nitidiusculus K. 5 at Bremen. 



On the island of Rugen I also observed the following, all skg. 



A. Diptera. Syrphidae'. 1. Volucella bombylans Z. B. Hymenoptera. 

 Apidae: 2. Apis mellifica Z. 5. C. Lepidoptera. Rhopalocera: 3. Pieris sp.; 



4. Vanessa urticae Z. 



