432 



LEPIDOPTERA 



The family Prodoxidae 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 

 mouth, exhibit a 

 remarkable modifi- 

 cation of instinct. 

 The facts are chiefly 

 known from the 

 observations of 

 Eiley ^ on Pronuha 

 yaccasella, 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 

 tlie 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 

 moth first visits the stamens, and collects, by the aid uf the 



^ " Tlie Yucca moth aud Yucca Pollination," Ecp. Missouri Botanical Garden, 

 1892, pp. 99-158. 



Fig. 208. — Pronuba synthetiva. Nortli America. A, Larva ; 

 B, C, ]uipa, ventral and lateral aspects ; D. female moth ; 

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

 labial palp ; h, maxillary tentacle ; c, maxillary palp ; 

 (/, proboscis : c, base of front leg. (After Riley.) 



