96 TRAifSACnONS AND PROCEEDINGS OF THE [Sess. lviii. 



its long spur, have long been a source of attraction. The 

 late Mr. Charles Darwin, upon asking himself the use of 

 this long spur, which performs the oflSce of a nectary, 

 came to the conclusion that the fertilisation of the flower 

 depended upon its length, as the nectar was only found 

 at the lower extremity ; and prognosticated the existence 

 in Madagascar of moths with probosces, capable of ex- 

 tending the length of 10 or 11 inches. In his book on 

 the Fertilisation of Orchids, he says : — " If the Angrmcv.m 

 in its native forests secretes more nectar than the vigorous 

 plants in our hothouses, so that the nectary becomes filled, 

 small moths might obtain their share, but they would not 

 benefit the plant. The pollinia would not be withdrawn 

 till some huge moth with a wonderful proboscis tried to 

 drain the last drop. If such great moths were to become 

 extinct in Madagascar, assuredly the Angrcecum would 

 become extinct also. On the other hand, as the nectar, at 

 least in the lower part of the nectary (spur), is stored safe 

 from depredation by other insects, the extinction of the 

 An^rorcum would probably be a serious loss to these 

 moths." At the time no moth with this character was 

 known, but since that date they have been, I believe, 

 found in the island. The flower has a powerful odour at 

 night, whereas by day it is quite scentless. 



ThinjJbergia lo.urifolw., Lindl. This is a beautiful winter 

 flowering tropical climbing plant, belonging to the order 

 Acanthaceae. It was described by Dr. Lindley in 1856. 

 The plant is a vigorous grower, resembling in the colour 

 of its flowers, to a certain extent, T. grandiflora, but 

 differing in its foliage, the species under notice having 

 elliptic, acuminate leaves, and quite glabrous, whilst those 

 of T. grandijlora are pubescent. Its racemes are produced 

 laterally from the stronger growths, and sometimes cany 

 as many as a dozen of the beautiful ultramarine blue 

 flowers. About the nodes there are a large number of 

 secretory glands. I^Ir. W. Gardiner, M.A, F.PuS., in a 

 paper read before the Cambridge Philosophical Society, 

 states that the secretion serves to attract ants, which, 

 besides feeding upon them, also protect the thin young 

 climbing shoots by attacking and destroying other creeping 

 insects of alien races with whom they may meet in their 

 passage up and down the stem. 



