i 4 ANGIOSPERMAE DICOTYLEDON ES 



stigmas, so that either cross- or self-pollination can be effected with equal ease by 

 insect-visits. At this later stage self-pollination is brought about automatically in 

 dull weather, for the flower then closes and the stigmas come into contact with the 

 pollen. Automatic self-pollination may also occur in sunshine, for as the flower 

 turns towards the sun, pollen readily falls upon the stigmas. 



Visitors. According to the observations of Hermann Miiller (H. M.), in 

 Thuringia, and myself (Kn.), in the garden at Kiel, the visitors are chiefly po-cltg. 

 bees, and po-dvg. flies and beetles. A. Coleoptera. (a) Coccinellidae: i. Micraspis 

 duodecimpunctata Z. (H. M.), 4 in a flower, one licking the stigmas. (b) Nilidu- 

 lidae: 2. Meligethes (Kn., H. M.), in very large numbers, po-dvg. B. Diptera. 



(a) Muscidae : 3. Scatophaga merdaria Z. (H. M.), po-dvg. (b) Syrphidae : 4. Eris- 

 talis sp. (Kn.) ; 5. E. tenax L. (Kn.), both po-dvg. C. Hemiptera. 6. Lygaeus 

 equestris L. (H. M.), very numerous, boring with their proboscis in the base of the 

 flower. D. Hymenoptera. (a) Apidae: Andrena nitida Fourcr. J, po-cltg. (H. M.); 

 8. A. parvula K. 5 (H. M.) ; 9. Apis mellifica Z. , freq. (Kn., H. M.) ; 10. Bombus 

 terrester Z. 5, settling, but neither skg. nor po-cltg. (H. M.); 11. Halictus albipes 

 F. $ (H. M.) ; 12. H. cylindricus F. $, freq. (H. M.); 13. H. morio F. <j> (H. M.); 



(b) Formicidae: 14. Formica congerens Nyl. $ (H. M.), very freq., busying itself with 

 anthers (po-dvg.?) and stigmas (skg. their moisture?). E. Thysanoptera. 15. 

 Thrips (H. M.), not infrequent. In some flowers a spider was found lurking 

 for prey. 



Loew observed the following in the Berlin Botanic Garden. A. Coleoptera. 

 Nitidulidae : 1. Meligethes sp., po-dvg. B. Diptera. (a) Muscidae: 2. Anthomyia 

 sp., po-dvg. (b) Syrphidae : 3. Melithreptus scriptus Z., po-dvg. C. Hymenoptera. 

 Apidae : 4. Andrena nitida Fourc. 5, po-cltg. 



31. A. aestivalis L. (Kerner, 'Nat. Hist. PI.,' Eng. Ed. 1, II; Knuth, 

 ' Bloemenbiol. Bijdragen.') The red or (in the variety A. citrinus Hoffman, some- 

 times considered a distinct species) yellow petals spread out in the sunshine, attracting 

 pollen-collecting bees and pollen-devouring flies. The flower mechanism agrees with 

 that of the last species, but owing to the smaller size of the flower there are fewer 

 insect visitors. 



Visitors. I observed in the Garden at Kiel. A. Diptera. Syrphidae: 

 1. Eristalis tenax Z., po-dvg. B. Hymenoptera. Apidae: 2. Apis mellifica Z. 5, 

 po-cltg. 



32. A. autumnalis L. (Knuth, ' Bloemenbiol. Bijdragen.') This agrees 

 with the last species as regards its flower mechanism. According to Warnstorf 

 (Abh. bot. Ver., Berlin, xxxviii, 1896), the flowers are homogamous and autogamous. 

 When the pollen is ripe, the stamens lie close to the purple stigmas. The pollen is 

 cinnamon-brown, and either irregularly elliptical with three longitudinal folds, or 

 tetrahedral with spheroidal faces. The grains in the former case are 43 /* long 

 and 25 fx. broad, in the latter case 31 ^ in diameter. 



Visitors. I observed only Apis mellifica Z. 5, po-cltg. 



8. Myosurus Dill. 



Flowers homogamous or protandrous with exposed nectar, secreted at the bases 

 of the small, inconspicuous, greenish-yellow petals. 



33. M. minimus L. (Sprengel, ' Entd. Geh.,' p. 443 ; Delpino, Altri appa- 

 recchi dicog. recent, oss.,' p. 57; Herm. Miiller, * Weit. Beob.,' I, pp. 316-18; 



