154 MISSOURI BOTANICAL GARDEN. 
EXPLANATION OF PLATES ILLUSTRATING YUCCA MOTH 
AND YUCCA POLLINATION. * 
PLATE 34, 
Fig. 1.— Pronuba yuccasella: a, larva; 6, 2 moth with 
closed wings; c, do. with wings expanded — nat. size; d, 
side view of one of the middle joints of larva; e, head of 
larva, beneath ; 7, do., above; g, thoracic leg of same; h, 
maxilla; ¢, mandible; 7, spinneret and labial palpi; &, 
antenna — enlarged. 
Fig. 2.— Pronuba yuccasella: moth soon after issuing 
from chrysalis, showing position of wings when expanding 
and before fully dried. x3. 
Fig. 3.— Pronuba yuccasella: generic characters —a, 
side view of head and neck of female denuded, showing 
how the collected load of pollen (1) is held by the tenta- 
cles (2); (3, 4, 5, tongue, antenna and maxillary palpi; ) 
6, maxillary tentacle and palpus; c, an enlarged spine; d, 
maxillary palpus of ¢; e, scale from front wing; f, front 
leg; g, labial palpus; h, 7, front and hind wings denuded ; 
Jj, anal joint of female with ovipositor partly extruded 
showing silk-like oviduct — all enlarged. 
Fig. 4.— Pronuba yuccasella: 1, male chrysalis; m, 
female do. 
Fig. 5.— Mature pods of Yucca angustifolia: a, artifi- 
cially pollinized and protected from Pronuba; 6, normal 
pod, showing constrictions resulting from Pronuba puncture 
and exit holes of larva; c, one of the lobes cut open show- 
ing larva within. 
PLATE 35. 
Fig. 1.—Flower of Yucca aloifolia showing stouter 
pistil and shorter style as compared with filamentosa. 
* The author is under obligations to Prof. Edwin Willets, Assistant 
Secretary of Agriculture, for the use of the illustrations Pl. 36, Figs. 
1, 2; Pl. 87, Fig. 2; Pl. 38, Fig. 2, and Pl. 41, Figs. 1,2. The others are 
either from his drawings and previously used, or made from his studies 
especially for this article, by Miss Lillie Sullivan. 
