MONANDRJE 45 



bees which make a habit of passing the night in their flowers, it is quite probable 

 that the flowers of C. calceolns fulfil a similar purpose. The lip of Serapias is covered 

 with erect somewhat yielding hairs, which may conduce to warmth and comfort for 

 the bees esconced among them, by supporting the weight of the body and resting 

 the legs of the insect. The lip of C. calceolus is similarly furnished, though some of the 

 hairs secrete a tiny drop of fluid at the tip, which may be edible, though Kurr states 

 he was unable to detect nectar within the labellum.i It is at least certain that various 

 species of Andrena enter the lip, and some spend the night there, and that none can 

 leave the flower without carrying off some of the pollen, and also depositing on 

 the stigma any pollen previously collected. 



The following species of Andrena were observed by H. Miiller to visit the flowers. 

 A. nigromea K. ?, A.fulvkrus K. $, A. albicans K. ?, A. atriceps K. ?, and A.pratensis 

 Nyl. ?. The fact that these were all females is in favour of the secretion of nectar. 

 A. parvula K. ? was repeatedly found dead within the labellum, probably owing to 

 frost, for a specimen placed by Darwin five times within the lip of C puhescens, 

 always managed to crawl out, covered with pollen. Various flies were also found 

 dead, viz. Empis punctata, a Cheilosia (Syrphid^e), an Anthomjia (Muscidas), and con- 

 siderable numbers oi Spilogaster semicinerea Wied. (Muscidae). Small beetles {Meligethes) 

 are able freely to creep out of the labellum, but sometimes stick on the anther-face 

 and die. 2 



Sub-family MONANBRJE 



Only one anther {A}, Text-fig. 2), normally fertile; lateral anthers of inner whorl 

 {ay and a'^') absent, or rudimentary (staminodes), very rarely developed through 

 atavism. Fertile stigmas two, confluent or lateral, the upper converted into a rostellum 

 (except in Cephalantherd). 



Monandry Swartz, Vet. Acad. Nja Handl. Stock, xxi, 205 (1800). 



The pollen-grains are dry, compressed into tetrads (fours), except in Cephalanthera, 

 and built up into pollen-masses (pollinia). The adhesive matter for attacliing them 

 to insects is secreted, not by the anther, as in the Diandras, but by the upper stigma, 

 which is transformed into the rostellum, a beautiful piece of mechanism peculiar to 

 the Monandras, and found in no other family of plants. The stigmas are coated with 

 an extremely adhesive secretion, to wliich the pollen-groups adhere so firmly on con- 

 tact, that they are torn away from the pollinia when these are withdrawn. 



I Bedeutung der Nektarien, p. 29 (i 8 3 3). Darwin could detect no nectar in the six species he examined, 

 C. harbatum, purpuratum, insigne, venustum, puhescens and acaulis {Pert. Orch. ed. 2, p. 229). 

 ' Miiller, toe. cit. pp. 539, 541. 



