REVISION OF MOTHS OF PRODOXINAE 23 



considered so by most botanists in the past. A majority of the botan- 

 ical texts in cmrent use place Yucca and Agave in separate families 

 largely on the basis of superficial ovarian structure. Yucca, with 

 its superior ovary, is placed usually in the family Liliaceae, and 

 Agave, which possesses an inferior ovary, in the Amaryllidaceae. 



In 1934 (later revised in 1959), Hutchinson presented a rather 

 revolutionary classification of this group of plants which reflected 

 the most recent opinions of several botanists; namely, that Yucca 

 and Agave are more closely related than was previously thought. 

 These two genera, along with several others, are recognized by 

 Hutchinson as comprising a single family, the Agavaceae, which is 

 distinct from both the Liliaceae and Amaryllidaceae. Hutchinson 

 emphasized this distmction even further by placing the Agavaceae 

 in a separate order, Agavales, along with the principally Austrahan 

 family, Xanthorrhoeaceae. 



Certain cytological evidence also suggests that Yucca and Agave 

 are closely related. Much of this information has been reviewed by 

 McKelvey and Sax (1933) and Granick (1944) and will be mentioned 

 only briefly in the present discussion. The evidence essentially 

 consists of strong karyotypic similarities between the two plant 

 genera in question. As pointed out by Granick, the ''Yucca-Agave" 

 karyotype is characterized by a diploid pattern of 10 large chromo- 

 somes on the periphery of the metaphase plate and 50 smaU ones, 

 slightly variable in size, concentrated in the center. The total 

 chromosome number, of course, may vary (as in polyploid Agave) 

 but the basic pattern is usually consistent. Because of its relative 

 uniqueness in the plant kingdom, the occurrence of this particular 

 karyotype is beheved to be very significant in indicating the basic 

 relationships of certain genera. In addition to Yucca and Agave, 

 this karyotype has also been found in Furcraea, Beschorneria, and 

 Polianthes, as well as in an Old World Hliaceous genus, Hosta. 



The present writer conciu-s with the conclusions of Hutchinson and 

 others in believing that Yucca and Agave are closely aUied. My 

 opinions are derived primarily from the affinities of the moths which 

 have evolved in association with this group of plants. The signifi- 

 cance of insect systematics as an indicator for taxonomic relationships 

 of other groups of animals and plants has been realized on numerous 

 occasions. This has been particularly true in situations involving 

 host-parasite associations or host-plant specificity. 



In regard to present entomological evidence, the close relationship 

 of Yucca and Agave are best shown by the apparent evolution of the 

 stem boring Prodoxinae. As discussed on page 17, it is possible that 

 a series of prodoxine genera have evolved, each being restricted to 

 a particular plant genus within the Agavaceae. This evolutionary 



