THE FLOWER AND THE BEE 



In their relations to flowers moths may })e divided into two 

 groups, the highly specialized hawk-moths {Sphinyidcc) and the 

 other moth families. Many moths fly only on the rainiest 

 and darkest nights. We should like to know more of the devious 

 ways of these nocturnal wanderers amid the down-pouring rain. 

 They seem a bit uncanny. Among the smaller moths most 

 frequently observed on flowers are the measuring-moths 

 (Geometridw), the leaf -rollers {Tortricidcc), the owlet moths or 

 noctuids (Xoctuidco), and the teneids or the little moths of the 

 family Teneidce, the larvae of which mine in leaves. Few of 

 them are common floral visitors, or of much significance in 

 pollination. Several of the hawk -moths, as the clear-winged 

 moths, fly regularly in the daytime. 



The yuccas, or Spanish bayonets, liliaceous plants which are 

 widely distributed in this country and Mexico, are entirely 

 dependent for pollination on little teneid moths of the genus 

 Pronuba. If the phenomena attending the transfer of the 

 pollen had not been investigated by Riley and Trelease in 

 every detail they would seem as incredible as a tale of Munch- 

 ausen. The large, pendulous flowers are creamy -white tinged 

 Avith green or rose, and are borne in magnificent clusters 

 or panicles, which are well worthy of the admiration they ex- 

 cite. Subtropical species of this genus become arboreal and 

 reach an altitude of 30 feet. In California Yucca Whipplei 

 sends up a flower-stalk 12 feet high, which for nearly half its 

 length bears an imposing cluster of flowers. (Fig. 66.) 



Since the large, bell-shaped flowers hang downward and the 

 stigmas stand in advance of the anthers, self-pollination is im- 

 possible, for the pollen is too glutinous to be carried by the 

 wind, and if accidentally dislodged, it falls directly to the 

 ground. The continued existence of the yuccas, therefore, 

 depends chiefly on the little moths of Pronuba. The female 



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