CISTINEAE 131 



Loew noticed Halictus rubicundus Chr. 5, skg., in Mecklenburg (' Beitrage,' 

 p. 41), and the following (op. cit., p. 33) in Silesia: A. Diptera. Syrphidae: 

 1. Syrphus balteatus Deg., skg. B. Hymenoptera. Apidae: 2. Apis mellifica 

 Z. ?, skg. 



Schenck observed 3 bees in Nassau: 1. Anthidium oblongatum Ltr. ; 2. A. 

 punctatum Ltr. ; 3. A. strigatum Ltr. 



Alfken saw the following at Bozen. 



A. Hymenoptera. Apidae'. 1. Coelioxys rufocaudata Sm. 5 and J, not in- 

 frequent, skg. ; 2. Halictus flavipes F. 5, freq., skg. and po-cltg. ; 3. Megachile pacifica 

 Pz. $>, freq. B. Coleoptera. (a) Buprestidae : 4. Acmaeodera flavo-fasciata Pill. 

 (&) Cerambycidae : 5. Clytus massiliensis L. ; 6. C. ornatus Hbst. 



Friese records the following Apidae for Baden (B.), Alsace (A.), Mecklenburg 

 (M.), Nassau (N.), and Hungary (H.). 



1. Prosopis bipunctata F. (B., A., M.) ; 2. P. confusa Nyl. (M.) ; 3. P. dilatata K. 

 (H.), not infrequent; 4. P. nigrita F. (M., H.); 5. Stelis signata Ltr. (N., according 

 !to Schenck). 



325. R. glauca L. The white flowers which were investigated by MacLeod 

 in the Pyrenees (Bot. Jaarb. Dodonaea, Ghent, iii, 1891, pp. 397-8) are aggregated 

 into conspicuous inflorescences. The nectary is a semicircular white disk on the 

 posterior side of the ovary. Nectar is secreted by its central part, which is partly 

 covered by the claw-lobes of the two upper petals, so that the secretion is only 

 visible from in front. The flowers therefore belong to the class EC. 



When the flower opens the four stigmas are mature, and may therefore be 

 cross-pollinated by insects. The anthers of the upper stamens dehisce subsequently, 

 ind those of the lower ones still later. Automatic self-pollination may result from 

 :he fall of pollen out of the upper anthers on to the stigma. 



Visitors. MacLeod observed Hymenoptera 6 species of Andrena, 2 of 

 Halictus, and one of Polistes and Diptera Syrphidae and Muscidae. 



XII. ORDER CISTINEAE DUNAL. 



White or brightly coloured pollen flowers, generally large, homogamous or 

 dightly protogynous. They open only in the sunshine, and usually remain open 

 jut for a short time (a few hours). The absence of nectar is compensated for 

 }y the production of large quantities of pollen. When cross-pollination is not 

 :ffected, autogamy is brought about by closure of the flowers. There are often 

 leistogamous flowers, as, for example according to M. Kuhn in species of 

 Lechea (Bot. Ztg., Leip., xxv, 1867, p. 67). 



no. Helianthemum Toum. 



Homogamous or protogynous pollen flowers, of which all the stamens are 

 ertile. 



326. H. vulgare Gaertn. (=H. Chamaecistus Mill., and Cistus Helianthemum 

 C). (Herm. Miiller, 'Fertilisation,' p. 117, ' Weir. Beob./ II, p. 210, Alpenblumen,' 

 )p. 1 6 1-2; MacLeod, ' Pyreneenbl.,' pp. 124-5; Knuth, ' Bloemenbiol. Bijdragen'; 



k 2 



