PLANTS AND INSKC'IS 113 



ing nectar, but pollinates the plant apparently with as 

 much intelligence as a human being would do it, Xot 

 for any benefit the moth itself may derive therefrom, 

 but that succulent seeds may be formed within the pod 

 upon which its yonng may be nourished. 



The yucca, or yucca lily as it is sometimes called, is 

 a familiar plant. Its white flower may be character- 

 ized briefly by the rather short, distinctly spreading 

 stamens, with the more extended pistil. The anthers 

 are so remote from the stigma that self-fertilization 

 can take place only by the merest chance. 



. */ 



The Pronuba moth is a showy white lepidopteron 

 about one-half inch long, and seems to have been con- 

 structed especially for a purpose in the life of the yucca. 

 The mouth of our common moths and butterflies con- 

 sists of the two long maxilla- united to form a proboscis, 

 used in reaching the deep-seated nectar of flowers such 

 as the honeysuckle. On each side of the proboscis, 

 near the base, is a mere protruding point, represent- 

 ing what is left of the once well-developed maxillary 

 palpi ; then there are two well-developed labial palpi 

 curving up from beneath the head on each side of the 

 proboscis, between which the proboscis is coiled up when 

 not in use. 



The female Pronuba moth, the yucca polleni/.er, lias 

 all of these, but the little protruding point on each side 

 of the proboscis is well developed into a four- jointed 

 palpus. From its base there arises a highly specialized 

 organ, which for want of a U-tter name we call the 

 maxillary tentacle. These tentacles are coiled somewhat 

 similar to the proboscis, but are readily distinguished 

 8 



