292 ANGIOSPERMAE—DICOTYLEDONES 



Besides hermaphrodite flowers, Schulz observed sporadic female ones, generally 

 growing on the same stocks as the former, though more rarely gynodioeciously dis- 

 tributed. Female flowers seem to occur more frequently in the South than in the 

 North. Mowes also often found flowers with partially or entirely reduced stamens. 



Visitors. — Alfken observed 7 humble-bees, skg., and Hoppner 12 bees, at 

 Bremen. — 



Alfken — i. Bombus agrorum F.^\ 2. B. arenicola Ths. J; 3. B. derhamellus 

 K. 5 ; 4. B. distinguendus Mor. 5, 5, and S ; 5. B. lapidarius Z. 5 ; 6. B. sylvarum 

 Z. 5; 7. B. terrester L. 5. Hoppner — i. Andrena convexiuscula K. 5; 2. Apis 

 mellifica Z. 5 ; 3. Bombus arenicola Ths. 5 and 5 5 4- B. distinguendus Mor. 5, 5, 

 and $ ; 5. B. hortorum Z. 5; 6. B. lapidarius Z. 5 ; 7- B. muscorum F. 5 and 5 ', 

 8. B. rajellus K. 5, 5. and S; g. B. sylvarum Z. $ and 5; i°- B. variabilis 

 Schmiedekn. §; 11. Podalirius borealis Mor. S; 12. P. retusus Z. 5 and S. 



Herm. Miiller (H. M.) and Borgstette (Borg.) give the following list. — 



A. Diptera. Syrphidae: i. Melanostoma mellina Z., po-dvg. (H. M.). 

 B. Hymenoptera. Apidae: 2. Andrena coitana K. 5 (Borg.); 3. Bombus 

 agrorum F. §, skg. (H. M.) ; 4. B. hortorum Z. $, in large numbers, do. (H. M.) ; 

 5. B. scrimshiranus A'^. J, skg. (H. M.) ; 6. B. sylvarum Z. §, do. (H. M.); 7. B. 

 terrester Z. j, obtaining nectar by perforation (H. M.). C. Lepidoptera. Rhopalocera : 

 8. Pieris rapae Z., skg., in large numbers (H. M.). 



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



Knuth, the humble-bee Bombus agrorum F., skg. Loew (Riesengebirge), do. 5, 

 po-cltg. Schulz, perforation by humble-bees. Herm. Miiller (Alps), 6 humble-bees. 

 Hoffer (Steiermark), 2 humble-bees — Bombus argillaceus Scop. 5 and 5. and B. 

 mastrucatus Gerst. MacLeod (Pyrenees), 2 humble-bees, skg. legitimately (Bot. 

 Jaarb. Dodonaea, Ghent, iii, 1891, p. 332) : (Flanders), a humble-bee, 2 hover-flies, 

 and a Muscid (op. cit. vi, 1894, p. 372). Willis (neighbourhood of S. coast of 

 Scotland), 2 humble-bees — Bombus agrorum F., skg., and B. terrester Z., freq., do. 

 (' Fls. and Insects in Gt. Britain,' Part 1). Scott-Elliot (Dumfriesshire), 4 humble- 

 bees and 2 hover-flies (' Flora of Dumfriesshire,' p. 139). 



2324. G. ochroleuca Lam. (Herm. Miiller, ' Fertihsation,' pp. 492-3, ' Weit. 

 Beob.,' Ill, p. 48 ; Schulz, ' Beitrage,' H, pp. 138-9, 221 ; Kerner, ' Nat. Hist. PI.,' 

 Eng. Ed. I, II, p. 356; Knuth, ' Bloemenbiol. Bijdragen.') — The flowers of this 

 species are yellowish-white in colour, with a yellow nectar-guide on the lower lip. 

 Their mechanism agrees essentially with that of G. Tetrahit (cf. Fig. 336, 4-6), 

 but the corolla-tube is 18-20 mm. long, the upper 6-7 mm. being so dilated that 

 a humble-bee can insert its head with ease, and a proboscis of 11-14 mm. long is 

 then able to suck all the nectar. The stigmatic branches project beyond the anthers 

 of the longer stamens, so that a humble-bee probing for nectar must always touch 

 the lower one first and bring about cross-pollination. Should insect-visits fail, 

 automatic self-pollination is ensured towards the end of anthesis by the bending of 

 the lower stigmatic branch until it comes below the anterior anthers, when it is 

 dusted by the falling pollen. Hermann Miiller says that the nectary is larger than 

 that of G. Tetrahit, enclosing the lower part of the two posterior sections of the 

 ovary, and projecting considerably beyond the two anterior. Kerner describes the 

 flower as protandrous. 



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

 stated. — 



