anrut.] THE MECHANISMS OF FLOWERS. 233 
_ A. Hymenoptera—Apide: (1) Prosopis armillata, Nyl. ? ; (2) Pr. 
 hyalinata, Sm. 2 ; (8) Halictus maculatus, Sm. ?, ¢.p.; (4) H. leucozonius, 
Schrank, 9, ¢p.; (5) H. sexstrigatus, Schenck, 9, c.p. and s.; (6) Andrena 
albicrus, K. ¢; (7) A. nana, K. ¢,s.; (8) Sphecodes gibbus, L. ¢,s.; (9) 
Nomada xanthosticta, K. ¢,s.; (10) N. succincta, Pz. ¢,s.; (b) Sphegide: 
(11) Ammophila sabulosa, L. ¢.  B. Diptera—Syrphide : (12) Syrphus 
reuatus, Fallen, fp. See also No. 590, 11. 
141. PoTENTILLA ANSERINA, L.—The floral mechanism resembles 
shat of P. verna. 
Visitors: Hymenoptera—(a) Apide : (1) Halictus flavipes, K. 9, cp. 
2) H. sexstrigatus, Schenck, 9, c.p. ; (b) Sphegide : (3) Oxybelus uniglumis, 
L; (4) O. bellus, Dib. See also No. 5y0, 11, and No. 609. 
142. PoreNnTILLA FRUTICOSA, L.—In this flower also I have 
failed to discover distinct drops of honey, but the smooth shining 
‘ing or disk at the base of the receptacular tube, surrounding the 
tigmas, is so much visited by insects, including even the honey- 
ee, that I can scarcely doubt that a thin layer of honey covers the 
pidermis in this part. The stigmas ripen simultaneously with the 
nthers, which dehisce laterally. Insects, as they happen to 
ight in the centre of a flower or on a petal, touch stigmas or 
tamens first, and thus cross-fertilisation and self-fertilisation seem 
qually probable. In absence of insects, some of the stamens curve 
vwards as they wither, and come, still dusted with pollen, in con- 
with the stigmas. In sunny weather the conspicuous flowers 
tract very numerous insects. 
Visitors: A. Hymenoptera—(a) Apidew: (1) Apis mellifica, L. §, ab. 
ne bee alights in the middle of the flower, and turning round passes its 
mgue over the whole honey-bearing ring which surrounds the bases of the 
ameus,—it effects cross-fertilisation regularly) ; (2) Halictus zonulus, Sm. 
}, also licking honey ; (0) Sphegide: (3) Oxybelus bellus, Dlb., very ab. 
ten four at once in a flower; (4) O. unigiumis, L., scarce, both licking 
mey. B. Diptera—(a) Stratiomyide: (5) Sargus cuprarius, L., ab. ; (d) 
abanide: (6) Chrysops cecutiens, L. ¢; (ce) Syrphide: (7) Eristalis 
pulcralis, L.; (8) E. arbustorum, L.; (9) Helophilus pendulus, L. ; (10) 
. floreus, L. ; (11) Melithreptus teeniatus, Mgn.; (12) Syritta pipiens, L. 
(11) all ab., sometimes 1.h., sometimes fp. ; (d) Conopide: (13) Sicus 
Tugineus, L.; (e) Muscide: (14) Sarcophaga carnaria, L.,ab. ; (15) Lucilia 
varum, Mgn.; (16) L. Cornicina, F., both ab.; (17) Anthomyia, very ab. ; 
8) Scatophaga merdaria, F., ab. ; (19) Sepsis, very freq. (12)—(18) only 1.h. 
_ Coleoptera—(a) Nitidulide : (20) Meligethes, very ab., fp. ; (6) Malaco- 
ermata ; (21) Dasytes flavipes, L., licking honey and devouring the anthers. 
143. Porentitta TorMENTILLA, Nestl.—The floral mechanism 
| iS as in P. verna, but the secretion of honey is more evident. The 
