2o8 TRANS. ST. LOUIS ACAD. SCIENCE. 



Length i. 25-1. 50 inches. Head bluish glassy-green, longer than broad, 

 the sides almost parallel; with dark ocelli-ground and rarely dark marks 

 in front and at base of antlers; shallowly punctate and quite pilose; the 

 antlers stout, with lateral prongs as stout as terminal. Color of body usu- 

 ally bright green, the dorsum paler or yellowish, with a deep blue medial 

 vascular line bordered each side by a paler yellow one. A subdorsal, 

 supra and substigmatal continuous straight line, each either white or 

 cream-color, and the two former either simple or bordered above with 

 green and below with blue-green ; the papillae quite prominent on the sub- 

 dorsal and substigmatal lines. 



Chrysalis — Differs only in being larger, in showing on the abdomen 

 traces of the pale longitudinal larval lines, and in having the mesonotal 

 ridge less angular. 



On the Ov /'position of the 7'ucca Moth. 

 By Chas. V. Riley. 



My last summer's observations have enabled me to complete 

 the natural history of Pronuba yuccasella ; and as a sequence to 

 what has already been published in the present volume of our 

 Transactions (pp. 55-64 and 178-180), I condense the facts as 

 to the method of oviposition from an article in the American Natu- 

 ralist (vol. vii. p. 619), where they are given at greater length. 



Analogy has proved a false guide, and the curious 5 Pronuba 

 adds to the anomalies which belong to her. Instead of being 

 thrust into the stigmatic opening, as I was most inclined to be- 

 lieve, the eggs are actually conveyed into the young fruit from its 

 side. The female, for the most part, gathers her load of pollen 

 from the contracted and curled anthers. In ovipositing she almost 

 always stations herself between two stamens, and, puncturing the 

 fruit with her ovipositor, conveys the egg to its destination. 



This egg is very narrow, elongate, soft, flexile, rather translu- 

 cent, pointed anteriorly, and of the exact color of its surrounding. 

 It lies curved in the ovarian cavity, always on the rounded side 

 next to the primary dissepiments, and with the anterior end gen- 

 erally close to the placenta. The operation of thus consigning an 

 egg lasts but a few seconds, and the ovipositor is no sooner with- 

 drawn than the moth runs up to the top of the pistil, uncoils her 

 pollen-bedecked tentacles, thrusts them into the stigmatic tube, 

 and works her head vigorously as previously described. 



