246 TRANS. ST. LOUIS ACAD. SCIENCE. 



Pedicidaris tiiberosa is yellowish-white, P. chaincedrys purple. In 

 Labiates the prevailing colors are blue, rose, lile.c, and purple ; 

 seldom yellow or white. Lamimn albutn^ hoivever, is white, while 

 Z. macidatum is red. Phloniis iuberosa is purple. Ph. Russeliatia is 

 yellow. Salvia ghiiinosa is yellow, S. pratensis blue. Why should 

 we have changes in color of such closely related species ! 



Hermann Miiller has shown that bees confine themselves in a 

 given visit to a given species. Now, much time would be con- 

 sumed in distinguishing between such closely related species as 

 Lamium alburn and JJ. macidatum. Miiller has shown that in- 

 sects, even Ifymenoptera, which have developed a high color- 

 sense, do not always distinguish between such flowers as Ranun- 

 culus acris, R. bulbosus, and R. repens ; and they even fly from 

 these to Potentilla verna and P. alpestris. This also occurs in 

 some genera where the nectar is seated somewhat deeper, as 

 in Mentha sempervivum, Androsace, and Compositce. Slight 

 changes in color must therefore be of great use to an insect, just 

 as changes in color of parts of a flower after pollination are of 

 use to the insect by indicating that its services are no longer 

 needed. Miiller believes that the changes in color, in closely 

 allied species, have been produced for reasons of this kind. 



PERFORATION OF FLOWERS. 



The perforation of flowers by insects, and in a few cases by 

 birds, to get at the nectar by fraudulent means, is a matter of com- 

 mon observation ; but in a few cases this is the normal way of 

 procedure, as has been shown by Darwin (34) and Miiller (91 La, 

 81 a, 82 b'), for insects are obliged to perforate the lax inner mem- 

 brane of some orchids (nearly all of the British Ophrea accord- 

 ing to Darwin) in order to get the nectar which lies within their 

 tissues; and in the case of Laburnum., etc., Miiller has shown 

 that insects puncture the thickened bases of the standard petal 

 in order to get nectar.* I ought also to call attention to the 

 destructive work of species of Megachile, which cut out parts of 



* That Lepidoptera should be capable of doing- this is not strange, since in Queensland 

 and Australia a moth {Ophideres fullonica) bores through the thick rind of an orange. 

 (Darwin, Fert. of Orchids, p. 40 ; see also a valuable paper on this subject by Breitenbach 

 in Jenasche Zcitschrift, 18S2, p. 157-214, PI. iv.-vi.) ^ 



