ROSACEAE 



39i 



the blossoms possess only a slight odour of honey; but at night (according to 

 Dr. Steudel of Stuttgart) they exhale an agreeable fragrance which attracts numerous 

 Noctuids. The erect stamens are at first crowded together in the middle of the 

 flower. Their unripe yellow anthers are either at the same level as the five already 

 mature stigmas, or (as figured by Hildebrand) as much as 5 mm. below them. 

 About two days after the bud has opened the anthers of the outer stamens begin 

 to dehisce, and afterwards those of the inner stamens. Meanwhile the stamens 

 diverge but little, so that in varieties where they are long automatic self-pollination 

 can readily take place. This may also occur when the flower fades, for at this 

 stage the styles curve outwards to such an extent that the stigmas are brought 

 into contact with the but slightly diverging stamens. Anthesis lasts from five to 

 six days. The interior of the flower is usually exposed without any protection 

 to the action of rain, to the influence of which 

 it appears to be very sensitive. Crossing is neces- 

 sary for the production of a good crop. Waite 

 says that self-pollinated flowers but rarely set fruits 

 (cf. p. 392). 



Visitors. I noticed the following in my 

 garden (' Bloemenbiol. Bijdragen '). 



A. Diptera. Syrphidac. 1. Syritta pipiensZ. 

 (14.5/96); 2. Syrphus balteatus Deg. (27. 5. '96); 

 both skg. and po-dvg. B. Hymenoptera. Apidae : 



3. Andrena parvula K. $, skg. and po-cltg. 



Herm. Miiller noticed the following. 



A. Diptera. (a) Bibionidae : 1. Dilophus vul- 

 garis Mg., in large numbers, skg. (b) Bombyliidae : 

 2. Bombylius major Z., skg. (c) Empidae: 3. 

 Empis livida L., skg. (d) Muscidae: 4. Onesia floralis 

 R.-D., skg. (e) Syrphidae : 5. Rhingia rostrata Z., 

 exceedingly numerous, mostly skg., but also po-dvg. 



po-dvg. B. Hymenoptera. (a) Apidae : 7. Andrena albicans Miill. & and 5, skg. 

 and po-cltg. ; 8. Anthophora pilipes F. $, do. ; 9. Apis mellifica Z. g, do. ; 10. Bombus 

 agrorum F. 5, very common, do.; 1 1. B. hortorum Z. 5, do. ; 12. B. lapidarius Z., do.; 

 13. B. terrester Z. $, do. ; 14. Halictus sexnotatus K. % skg. ; 15. Osmia rufa Z. J, 

 do. (6) Formicidae: 16. Several species, freq., skg. 



Alfken, at Bremen, noticed a dragon-fly (Agrion minimum Harr.), freq., busy 

 about the flowers, though the nature of its activity was not determined; also the 

 following bees. 



1. Andrena albicans Miill. $; 2. A. albicrus K. $; 3. A. convexiuscula K. $; 



4. A. varians K. $ ; 5. Bombus agrorum F. 5 ; 6. B. hortorum Z. <j>; 7. B. terrester 

 Z. 5 ; 8. Halictus calceatus Scop. <j> ; 9. H. levis K. $ ; 10. Osmia rufa Z. $ and S; 

 11. Podalirius acervorum Z. $. 



The following were recorded by the observers and at the places stated. 



Krieger (Leipzig), a bee (Bombus hortorum Z. $). Smith (England), a bee 

 (Andrena fulva Schr.). Plateau (Belgium), bees (Apis, Andrena fulva Schr., and 

 Bombus terrester Z.), a wasp (Vespa germanica F.), and flies (Calliphora vomitoria 

 Z., Musca domestica Z., Lucilia caesar Z., and Eristalis tenax L.). 



FIG. 123. Pyrus Malus,L. (after Hilde- 

 brand). Flower seen from the side ; the 

 stigmas projecting beyond the anthers. 



6. Syrphus pyrastri Z., skg. and 



