620 ANGIOSPERMAEDICOTYLEDONES 



1467. A. rigescens Willd. 



Visitors. Loew observed a Muscid (Anthomyia sp.) and 3 Syrphids (1. Eristalis 

 tenax Z. ; 2. Melanostoma mellina Z. ; 3. Syritta pipiens L.) in the Berlin Botanic 

 Garden. 



1468. A. Cotula L. Ludwig states that the white ray-florets are neuter and 

 usually 8 or 13 in number. 



455. Matricaria L. 



Ray-florets ligulate, white in colour, sometimes wanting ; disk-florets hermaphro- 

 dite, yellow. Structure of style as in Achillea (cf. Fig. 202, 10). 



1469. M. Chamomilla L. (Ogle, Pop. Sci. Rev., London, ix, 1870, pp. 160-4 ; 

 Herm. Miiller, 'Fertilisation,' p. 332, ' Weit. Beob.,' Ill, p. 86 ; Knuth, 'Bl. u. Insekt. 

 a. d. nordfr. Ins.,' pp. 91, 158 ; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893.) 

 The diameter of the entire head in this species is 18-24 mm., that of the disk 6-8 mm. 

 Hermann Miiller points out that as the florets mature in centripetal order, the common 

 receptacle rises up into a cylinder terminated by a blunt cone. The florets which 

 are over cover the cylinder, and the closed ones the cone, while the region actually in 

 flower comes between the two. The last is naturally the part first touched by 

 alighting insects, so that visitors constantly settle on the best place for obtaining 

 booty, and for effecting pollination. In other respects the flower mechanism agrees 

 with that of Anthemis arvensis. 



Visitors. These are more especially flies, while the strong odour of the heads 

 is disagreeable to bees, with the exception of species of Prosopis. 



Herm. Miiller (H. M.) and Buddeberg (Budd.) give the following list. 



A. Coleoptera. (a) Cerambycidae : 1. Leptura livida Z. f not infrequent 

 (H. M.); 2. Strangalia attenuata Z., do. (H. M.). (b) Nitidulidae; 3. Meligethes, 

 freq. (H. M.). B. Diptera. (a) Empidae: 4. Empis livida Z., skg. (H. M.). 

 (b) Muscidae: 5. Lucilia cornicina F. (H. M.); 6. Pollenia vespillo F., po-dvg. 

 (H. M.)j 7. Sarcophaga carnaria Z., freq., po-dvg. (H. M.); 8. S. haemorrhoa 

 Mg., po-dvg. (H. M.); 9. Spilogaster nigrita Fall. (H. M.). (c) Stratiomyidae : 10. 

 Nemotelus pantherinus Z., very common, skg. (H. M.). (d) Syrphidae: 11. Eristalis 

 arbustorum Z., very common, po-dvg. (H. M.); 12. E. nemorum Z., do. (H. M.); 

 1 3. E. sepulcralis Z., do. (H. M.) ; 14. Syritta pipiens Z., do. (H. M.). C. Hymeno- 

 ptera. (a) Apidae: 15. Colletes daviesanus K. $, in large numbers, skg. (Budd.); 

 16. Halictus nitidus Schenck $, skg. (Budd,); 17. Prosopis signata Pz. 5 and S, 

 freq., alternately settling and flying away (H. M., Budd.); 18. Sphecodes gibbus Z. 

 $ and J (H. M.). (b) Sphegtdae: 19. Oxybelus uniglumis Z., freq. (H. M.). 



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



Knuth (North Frisian Islands), Apis, 9 flies, a Lepidopterid, and a beetle. 

 Schletterer (Pola), the dasygastrid bee Eriades truncorum Z. MacLeod (Flanders), 

 a humble-bee, 2 Lepidoptera, and 7 beetles (Bot. Jaarb. Dodonaea, Ghent, v, 

 ^93, p. 424). Saunders (England), the two bees Colletes daviesanus K. and C. 

 picistigma Thorns. Krieger (Leipzig), the very common bee Colletes daviesanus A". 



1470. M. inodora L. (= Chrysanthemum inodorum Z.). (Knuth, 'Bl. u. 

 Insekt. a. d. nordfr. Ins.,' pp. 91, 158; Herm. Miiller, 'Fertilisation,' p. 331, 'Weit. 

 Beob.,' Ill, p. 86.) The flower mechanism of this species essentially resembles that 

 of Anthemis arvensis. Ludwig states that the almost odourless heads usually contain 

 13 or 21 ray-florets. 



