432 



LEPIDOPTERA 



CHAP. 



The family Frodoxidae consists of some Tineids, the larvae of 

 which feed in the pods and stems of the Yuccas of south-western 

 North America ; they have the mouth of very unusual form 



(Fig. 208, E), and 

 some of them, by 

 aid of this peculiar 

 month, exhibit a 

 remarkable modifi- 

 cation of instinct. 

 The facts are chiefly 

 known from the 

 observations of 

 Eiley 1 on Pro-nulm 

 yuccasella, a moth 

 living on Yucca 

 filamentosa ; this 

 plant has been in- 

 troduced into our 

 gardens in this 

 country, where it 

 never, we believe, 

 produces seed. The 

 Yuccas are not 

 fitted for self-fertil- 

 isation or for fer- 

 tilisation by Insect 

 agency of an. ordi- 

 nary kind. The 

 progeny of the 

 moth develops in 

 the pods of the 

 plant, and as these 

 cannot grow until 

 the flowers have 

 been fertilised, the moth has the habit of fertilising the flowers 

 at the time she lays her egg in the part that is to develop into 

 the pod, and to be the food for her own progeny. The female 

 inoth first visits the stamens, and collects, bv the aid of the 



FIG. 208. Pronuba .tynthefim. North America. A, Larva : 

 B, C, pupa, ventral and lateral aspects ; D, female moth ; 

 E, head and part of thorax of the female moth : a, 

 labial palp ; b, maxillary tentacle ; c, maxillary palp ; 

 d, proboscis ; e, base of trout leg. (After Riley.) 



1 "The Yucca moth and Yucca Pollination," Hep. Missouri Botanical Garden, 

 1892, pp. 99-158. 



