RILEY GENUS PRONUBA J FERTILIZATION OK YUCCA. 6l 



For want of sufficient time I have been unable to catch the moth 

 in the act of oviposition ; but from careful examination I am satis- 

 tied that the eggs are not deposited on the outside of the fruit. 

 They are either thrust into it from the side or from the stigmatic 

 opening, following, most probably, the course of the pollen tubes. 

 I strongly incline to the latter view, for, though many Lepidoptera 

 are furnished with extensile ovipositors which enable them to 

 thrust their eggs into crevices and other orifices, I know of none 

 which actually puncture. Nor have I been able to discover any 

 trace of punctures leading to eggs. 



Neither have I been able to discover the egg in situ; which 

 is not to be wondered at, however, as when examined in the 

 female abdomen it is found to be long, narrow, soft, and flexible, 

 and of the exact color of the flesh of the young fruit. The ovi- 

 positor is so very fine and extensile that it may be thrust into the 

 most minute and narrow passage. 



If, a day or two after the flowers have withered (between June 

 15 and July 5 in the latitude of St. Louis with the species men- 

 tioned), we carefully dissect the young fruit, we shall often find it 

 to contain from one to half a dozen, but more generally two, young 

 larva.'. They are always found within the nascent seed, and their 

 bodies are, at this time, so much of a color and consistence with 

 the surrounding pabulum, that we could hardly detect them but 

 for the comparatively large, dark jaws. The larva retains its white 

 color till after the last molt, when it acquires the carneous tint so 

 common, at that age. to fruit-boring moth larvae. It is then char- 

 acterized as follows : 



Description of Larva. — Average length 0.55 inch. Broadest on thora- 

 cic joints, thence gradually decreasing to extremity, which is quite small. 

 (Fig. 2, a.) Color carneous, with a paler greenish tint below. No pilifer- 

 ous spots, but a few very minute and short stifl' hairs springing from the 

 ordinary positions of such spots. A transverse dorsal wrinkle, on each of 

 the principal joints, more or less distinctly divided in two by a medio- 

 dorsal depression which is sometimes slightly bluish. Joints deeply incised 

 and with a lateral, substigmatal, longitudinal wrinkle. (Fig. 2, d.) Tho- 

 racic legs stout, but short, with three joints and a claw. No prolegs. Stig- 

 mata (9 pair) forming a small rufous circle on anterior portion of joints 1 

 and 4-11. Head (Fig. 2, e,f, k, i,J. k) partially retractile, copal-colored; 

 epistoma sharply defined ; labrum slightly pilose ; mandibles stout, rounded, 

 and with four acute teeth, each diminishing in size from without; maxillae 

 with the inner lobe rounded and furnished with (usually 2) short fleshy 

 hairs, the palpi 4-jointed, the terminal joint with bristles; labium promi- 



