132 THE FERTILISATION OF FLOWERS. [PART III. 
in the likelihood of cross-fertilisation in case of insect-visits, and 
of self-fertilisation in their absence. They are equally con- 
spicuous, and are visited to about the same extent. 
Visitors : A. Diptera—(a) Stratiomyide : (1) Stratiomys sp., s. (6) Empide: 
(2) Empis opoca, F.; (3) E. rustica, Fallen, both very ab., s. ; (c) Leptide: 
(4) Leptis strigosa, Mgn., s. ; (d) Syrphide : (5) Eristalis nemorum, L. ; (6) E. 
arbustorum, L. ; (7) E. sepulcralis, L. ; (8) Syritta pipiens, L., all four ab., 
s.; (9) Platycheirus manicatus, Mgn., ab.,s.; (10) Syrphus, sp., s.; (11) 
Melanostoma mellina, L., s. ; (e) Muscide : (12) Sepsis ; (13) Anthomyia etiva, 
Mgn.,s. B. Hymenoptera—Apide: (14) Andrena argentata, Sm. 9, s. ; (15) 
A. albicans, K. 9, s. ; (16) Halictus, ? (the size of H. nitidiusculus)s. C. Cole- 
optera—Staphylinide : (17) Omalium florale, Pk. D. Thysanoptera: (18) 
Thrips, frequent in the base of the flower. E. Lepidoptera—(19) Polyom- — 
matus Phloeas, L., s. See also No. 590, 11., and No. 609. 
Fia. 41.—Cerastium arvense, L. 
1.—Flower in first stage. The outer whorls of anthers are covered with pollen, the inner are not 
yet full grown ; the styles are curled inwards. 
2.—F lower at the end of the third stage. The outer anthers are in part fallen off, and in part — 
withered ; the inner are still sparingly coated with pollen; the stigmas are mature. 
61. CERASTIUM TRIVIALE, Link, has smaller flowers and fewer : 
insect-visitors ; accordingly it is less markedly proterandrous than — 
C. arvense. It produces seed by self-fertilisation in the absence of 
insects (Axell, 17). 
Visitors : Diptera—(a) Syrphide: (1) Syritta pipiens, L., s. and fp. ; 
(b) Empide: (2) Empis livida, L., s. 
62. CERASTIUM SEMIDECANDRUM, L., has still smaller flowers 
and is still less frequently visited than the preceding species; it is — 
still less distinctly proterandrous, and fertilises itself regularly in 
absence of insects. | 
As in Stellaria media, the inner honeyless stamens are usually 
abortive, but remains of their filaments, sometimes attaining half _ 
the length of the outer stamens, frequently remain. When the 
anthers dehisce, they occupy the middle of the flower, and the 
stigmas still lie close together, though their tips are bent outwards 
and easily receive pollen. Later, the anthers pass outwards, the 
stigmas lengthen slightly and spread out, turning their imner 
