180 THE FERTILISATION OF FLOWERS. [PART II. 
those of M. falcata, on the other hand, for bees; yet I am not able 
to account for this difference in attractiveness. 
Visitors, at Rehmberg, Thuringia, July, 1868 :— 
A. Hymenoptera—Apide : (1) Apis mellifica, L. §, s., freq. ; (2) Bombus 
muscorum, F. $,s.; (3) Rhophites canus, Ev. ? 2, +. ; (4) Cilissa leporina, 
Pz. 2 ¢, s. and c.p.; (5) Andrena denticulata, K. 2, s.; (6) A. fulvicrus, 
K. 92, .8.; (7) Halictus quadricinctus, F. 9, cp. ; (8) Nomada Solidaginis; 
Pz. 9,8.; (9) N. varia, Pz. 9,8. ; (10) N. ferruginata, K. 9,s.; (11) Osmia 
aurulenta, Pz. 9, s. and «p., ab. B. Diptera—(a) Bombyliide: (12) Sys- 
teechus sulfureus, Mik., s.; (b) Syrphidw: (13) Helophilus trivittatus, F. 
©. Lepidoptera—(a) Ehopalocera: (14) Hesperia, s.; (15) Lyceena, s.; (0) 
Sphinges: (16) Sesia asiliformis, Rott., s.; (17) Zygeena carniolica, Esp., ab. ; 
(c) Noctue: (18) Euclidia glyphica,. L., s. Four additional visitors (ia ry 
doptera) are recorded in No. 590, II. 
95. MerpICcCAGO LUPULINA, L.—The flowers ‘of this species, 
whose upper stamens seem to possess very little elasticity, are — 
exceedingly minute but yet attract many diligent visitors. 
A. Hymenoptera—Apide : (1) Apis mellifica, L. §, s., very freq. (It is 
characteristic of the honey-bee that it does not disdain even this flower’s tiny 
store of honey. The whole inflorescence is pulled down by the weight of the 
bee, which then sucks the flowers head downwards. It sucks a few flowers, at 
most four, on one inflorescence, and then flies away to another plant of the same _ 
species ) ; (2) Andrena convexiuscula, K..9,s.; (3) A. xanthura, K. 9,¢p.; — 
(4) Halictus flavipes, K. 9, c.p.; (5) Bombus agrorum, F.? §, s. B. 
Diptera—Conopide: (6) Myopa buccata, L., s.; (7) M. testacea, L., s. 
C, Lepidoptera—Rhopalocera : (8) Thecla rubi, L. 9, s. 
Darwin also saw MZ. lupulina visited abundantly by bees. He i 
found the plants very much less fertile when protected from insects 
by a net. 
96. MELILOTUS OFFICINALIS, Willd.—The mechanism of the flower — 
resembles that of 7'rifoliwm repens, with certain slight variations. 
The calyx is much shorter (only 2 mm. long) and at the same — 
time wider, thus admitting insects with shorter tongues to the 
honey, and also giving greater range of movement to the petals. 
The alz and carina can rotate much farther downwards, since their 
claws are not adherent to the staminal column as in 7. repens, 
Their return to their former place when relieved from pressure is — 
insured by two finger-like processes (/) which replace the pouches of 
1’. repens at the superior basal angle of the ale; they grasp the 
staminal column superiorly, and, when the carinz are drawn down, 
they separate slightly but still remain closely applied to the 
