iHAP. VI] 



ANIMALS 



13' 



mention orchids. The beauty and 

 cent of many tropical Lepidoptera 

 !enote correspondingly developed 

 enses of colour and smell, and the 

 irge blue Morphos of South America 

 nd the brilliant bird-like Malayan 

 )rnithoptera are very common in 

 heir native countries. But some 

 dditional characteristics of many 

 ropical Lepidoptera may be con- 

 idered here. Thus many tropica! 

 owers have enormously long tubes 

 Fig. 66), at the base of which there 

 i nectar, which can be reached only 

 }• moths with a correspondingly 

 )ng proboscis. The longest struc- 

 u'es of this kind are the spur-like 

 ockets of the labcllum of Macro- 

 lectrum sesquipedale, Pfitzer, a 

 ladagascar orchid, which are five 

 ecimeters long (Fig. 67). Some 

 ■opical Rubiaceae cultivated in the 

 otanic garden at Buitenzorg at- 

 ■acted my attention by the unusual 

 :ngth of their corolla-tubes (Fig. 

 S) ; moths with a proboscis suffi- 

 ently long to be able to suck the 

 :ctar that is at their bases do not 

 cur in Europe, and possibly not 



any part of the north temperate 

 jne. 



Macroplectrum sesquipedale may 



one of these species whose very 

 :stricted geographical distribution 



connected with that of a genus 



species of insect that pollinates 

 lem. An indubitable case of this 

 iture is exhibited by several North 

 merican species of Yucca, which 

 e exclusively pollinated by moths 



the genus Pronuba. Thus Yucca 

 amentosa, which is frequently grown 



our gardens but always remains 

 K 2 





Fig. 67. Flowers of 



Macroplectrum sesqui- 

 pedale, Pfitzer. All 

 the perianth, with the 

 exception of the spur, 

 removed. In the bo- 

 tanic garden, Heidel- 

 berg. Natural size. 



