PART III. | THE MECHANISMS OF FLOWERS. ~ at 
_ anthers dehisce at their edges, and are only covered with pollen 
at these parts. In absence of insects, I have noticed, in the case of 
_ plants blooming in my room, that some pollen falls at length upon 
the stigmas, in consequence of the oblique (light-seeking) position 
of the flower. 
Visitors: A. Diptera—(a) Empide: (1) Empis livida, L., s.; (b) Syr- 
_ phide: (2) Eristalis sepulcralis, L., s.; (8) Syrphus, s.; (4) Melithreptus 
_ menthastri, L., s. ; (5) Rhingia rostrata, L., s. ; (6) Syritta pipiens, L., s., ab. ; 
_ (c) Muscide: (7) Anthomyia sp. ; (8) Musca corvina, F. B, Coleoptera— 
(a) Dermestide : (9) Anthrents pimpinelle, F., 1h.; (10) A. scrophularia, 
iL, Lh. ; (b) Nitidulide: (11) Meligethes, ab.; (c) Malacodermata: (12) 
_ Dasytes flavipes, F. ; (13) Malachius bipustulatus, F., both species licking 
honey, and also devouring the anthers; (d) Mordellide : (14) Mordella acu- 
 leata, L., lh. ; (e) Cerambycide : (15) Grammoptera ruficornis, Pz., not rare, 
1h., and also devouring the anthers. C. Thysanoptera—(16) Thrips, ab., s. 
_D. Hymenoptera—(a) Apide : (17) Prosopis communis, Nyl. 2; (18) Hal- 
_ ictus’ lucidulus, Schenck, 9, s. ; (19) H. sexstrigatus, Schenck,? ; (20) An- 
drena dorsata, K. 2, ¢.p.; (21) Nomada sexfasciatus, Pz. ¢; (22) N. rufi- 
 cornis, L. 2, s,; (23) N. signata, Jur. ¢,s.; (24) Apis mellifica, L. $, cp. ; 
_ (b) Sphegide : (25) Oxybelus uniglumis, L., Lh, See also No. 590, 1, and 
No. 609. 
In the United States, cultivated species of Fragaria incline to 
- dicecism. 
: 139. PoTENTILLA VERNA, L.—The annular ridge on the inner 
wall of the receptacular tube, which surrounds the base of the 
stamens and is marked by its dark, sometimes reddish-yellow, 
colour, and bright polished appearance, secretes honey not in drops 
but in a very evident smooth adherent layer. The anthers get 
covered on both sides with pollen, and ripen simultaneously with 
the stigmas. Insect-visitors alight sometimes in the middle of the 
flower, sometimes on the petals ; in the latter case they dust them- 
selves with pollen, but are not likely to come in contact at all with 
the stigmas, as the honey-secreting ring lies farther outwards than 
| in the preceding species ; if they alight in the middle of the next 
flower, cross-fertilisation is accomplished. Self-fertilisation must 
in any case be a frequent occurrence. In dull weather the flowers 
close partially, and at night they shut completely, bringing the 
anthers in contact with the stigmas. 
Visitors (from April 21 to May 24): A. Hymenoptera—Apide : © 
“Halictus leucopus, K. 9,s. and cp. ; (2) H. flavipes, K. ?,¢.p.; (3) H 
-sexstrigatus, Schenck, 2, c.p.; (4) H. cylindricus, F. 2, cp. ; (5) Andrena 
albicans, K. 2 ¢, ep. and s., ab. ; (6) A. albicrus, K. ¢,s.; (7) A. nana, K. 
: | = s.; (8) A. argentata, Sinith (= A. gracilis, Schenck), g,s.; (9) A. fulvi- 
