354 ANGIOSPERMAE—DICOTYLEDONES 



A. elegans) at Rio de Janeiro, and found that the fly visitors, some of which are 

 imprisoned, effectually pollinate the stigma. 



Visitors. — The following flies were recorded by the observers stated. — 



Herm. Miiller — {a) Muscidae : i. Myodina vibrans Z. ; 2. Sapromyza apicalis 

 Loew, very freq. {b) Phoridae : 3. Phora pumila Mg. Delpino (' Ult. oss.') — 

 I. Phora nigra Mg.; 2. P. pumila Mg.; 3. Ceratopogon aristolochiae Pond.; 

 4. Lonchaea tarsata Fall. 



2492. A. altissima Desf (Delpino, ' Ult. oss.,' p. 28.) — The flower mechanism 

 of this species deviates but little from that of A. Clematitis. 



Visitors. — Delpino observed 3 flies (determined by Rondani) — i. Ceratopogon 

 lucorum Mg. ; 2. Phora pumila A/g. ; 3. P. pulicaria Fall. 



2493. A. rotunda L. and 2494. A. pallida Willd. (Delpino, loc. cit.) — The 

 flower mechanisms of these species differ but little from that of A. Clematitis. The 

 joint-cell of the weel-hairs is thin-walled on its under-side, but generally thickened 

 above, and provided with a thin porous spot just in front of the septum dividing it 

 from the foot-cell. Correns thinks this may be a protection against fracture as the 

 result of pressure. Correns describes the flowers of A. pallida as larger than those of 

 A. Clematitis. Ti.'ey always grow singly and quite upright ; their perianth is green 

 in colour, with a cres'centic brown-black patch opposite the excavated side. Five or 

 six streaks of the same colour reach from this down the funnel-shaped tube into the 

 short, cylindrical trap. This is beset with long hairs, which stick together later on. 

 The tube is lined with weel-hairs resembling those of A. Clematitis. An imperfect 

 closure of the perianth tube takes place towards the end of anthesis by the bending 

 down of its lip. 



Visitors. — Delpino (' Ult. oss.') observed 3 flies (determined by Rondani) in the 

 flowersof A. pallida — i. Phora carbonariaZ<?//.; 2. P. pulicaria /a//.) ; 3. Chironomus 

 gracilis Macq. (?). 



The flowers of A. rotunda also grow singly and always upright. The green 

 perianth possesses a narrow, cylindrical tube, which ends in a comparatively large, 

 flat limb, brown- black on its inner side. After the anthers have dehisced, it bends 

 sharply backwards and downwdrds, folds up round the perianth tube, and so closes 

 the flower entrance completely. The weel-hairs situated in the perianth tube resemble 

 those of A. Clematitis, but the barrier apparatus is more perfect. Both A. rotunda 

 and A. pallida possess abundani" ' twining-hairs ' on the outer wall of the perianth 

 and on the ovary. These consist of a basal cell (sometimes subdivided), one or two 

 intermediate cells (neck-cells), and one reflexed hook-cell, which lies parallel with 

 the perianth wall (the opening of t,he hook directed upwards). 



Visitors. — Delpino observed 7 flies (determined by Rondani) in A. rotunda. — 

 I. Scatopse nigra Mg.; 2. Cerat )pogon minutus Mg.; 3. Sciara minima Mg.; 

 4. Cecidomyia atricapilla i?c«a'. ; 5. Oscinis aristolochiae y?o«(/.; 6. O. delpinii i?o«rf. ; 

 7. O. dubia Macq. 



2495. A. fimbriata Cham. (= A. Bonplandi Tenore). — Hildebrand says (Bot. 

 Ztg., Leipzig, xxviii, 1870, p. 603) thalt this species agrees with A. Sipho in the shape 

 of its perianth, and with A. Clematitis I'ln the arrangement of the weel-hairs. 



