346 ANGIOSPERMAE DICOTYLEDON ES 



probing the base of a flower to get the nectar secreted on the inner surface of the 

 receptacle generally touch the stigma and pollen with opposite sides of their heads, 

 and therefore effect cross-pollination. Pollen-devouring insects, on the other hand, 

 bring about cross- and self-pollination indifferently. 



Visitors. I observed the following at Kiel (' Bloemenbiol. Bijdragen '). 



A. Diptera. Syrphidae: i. Eristalis arbustorum Z., skg. ; 2. Rhingia rostr 

 Z., do. B. Hymenoptera. Apidae : 3. Apis mellifica Z. . skg. ; 4. Bomt 

 lapidarius Z. $ and $, do. 



Herm. Miiller records the following for Jena (' Weit. Beob.,' II, p. 244). 



A. Coleoptera. (a) Cerambycidae : 1 . Tetrops praeusta Z. (&) Chrysomelida 

 2. Haltica sp. B. Hymenoptera. Apidae : 3. Anthophora aestivalis Pz. $ and 

 skg. and po-cltg. ; 4. Apis mellifica Z. $f, do. ; 5. Halictus maculatus Sm. $, po-cltg.; 

 6. Osmia aurulenta Pz. $ and $, skg. ; 7. O. fusca Chr. 5, po-cltg. 



Loew noticed the following bees in Brandenburg (' Beitrage,' p. 37). 



1. Andrena combinata Chr. 5, skg.; 2. A. nigroaenea K. % do. ; 3. A. pilipes F. 

 5, do. ; 4. A. tibialis K. $, do. ; 5. A. varians AT., var. helvola Z. 5, do. ; 6. Nomada 

 alternata K. t> ; 7. Osmia rufa Z. $, skg. 



MacLeod saw Apis, and Bombus terrester Z., in Flanders (Bot. Jaarb. Dodonaea, 

 Ghent, vi, 1894, p. 323). 



825. P. Cerasus L. The results of Kirchner's investigations on this species 

 (' Beitrage,' pp. 34-5) differ in not unimportant particulars from the account given 

 by Sprengel and Miiller. The flowers smell like bitter almonds, and are mostly 

 borne upon horizontal stalks, though not infrequently these may be directed obliquely 

 upwards or downwards. The petals spread out to form a flat surface, of which the 

 diameter is 28-31 mm. (on an average 30 mm.). The anthesis of individual flowers 

 fasts 7-8 days. The flowers are protogynous (Herm. Miiller described them as homo- 

 gamous). The stigma is at about the same level as the anthers of the longest stamens. 



When the flower opens, the stigma is already mature, but the anthers are all 

 closed, so that at this stage insect visitors must effect cross-pollination. While the 

 flower is fully expanding, the anthers of the inner stamens begin to dehisce in 

 the course of the first day. Dehiscence is centrifugal and extrorse, so that in the 

 great majority of flowers automatic self-pollination cannot take place. 



Visitors. I observed a small bee, Andrena albicans, Miill. J, skg., at Kiel 

 (' Bloemenbiol. Bijdragen '). 



Schmiedeknecht saw Bombus pratorum Z. 5, in Thuringia, and Schenck 2 

 cuckoo-bees in Nassau. 1. Nomada fabriciana Z., var. nigrita Schenck) 2. N. 

 rhenana Mor. 



Alfken and Hoppner (H.) observed the following bees at Bremen. 



1. Andrena albicans Miill. 5; 2. A. albicrus K. 5; 3. A. argentata Sm. $; 

 4. Bombus agrorum F. 5 (H.) ; 5. B. derhamellus K. 5 (H.) ; . 6. B. lapidarius Z. J 

 (H.) ; 7. B. terrester Z. % (H.) ; 8. Nomada alboguttata H.-Sch. S ; 9. Osmia rufa 

 Z. ? . 



Bees were also noticed as follows. 



Friese (Mecklenburg), Osmia rufa Z. 5. Loew (Brandenburg), Andrena pro- 

 pinqua Schenck ('Beitrage,' p. 37). Plateau (Belgium), 1. Andrena fulva Schr. (=A. 

 vestita F.); 2. Apis; 3. Osmia bicomis Z. 



In Dumfriesshire Apis and a parasitic humble-bee have been recorded (Scott- 

 Elliot, ' Flora of Dumfriesshire,' p. 53). 



