Development and Trdiixjnnnalionx '>/ Pronuha. 03 



thiit in all other Lepidoptera that I know of the tongue is a 

 smooth organ and in no way armed, except near the tip. In 

 short, the tongue in Pronnha mamlaia has become an accessory 

 tentacle, serving and helping in pollination, but probably in- 

 cai)al)le of use for feeding purj)oses. These structural peculiari- 

 ties justify the conclusion, which observation confirms, that Pro- 

 nuba does not feed in the imago state. In other words, she has 

 no incentive to go to the stigma with her load of pollen other 

 than that of pollinizing, and the slight amount of nectar which 

 the plant secretes is Avell calculated to lead other insects which 

 seek it away from the stigma and thus not to interfere with Pro- 

 nuba's mission. 



Development and Transformations of Pronuba. 



On this subject I need only remark that the action of ovii)osi- 

 tion causes a disorganization of the plant tissue in the immediate 

 neighborhood of the apical portion of the egg and the swelling 

 of the adjacent ovules ; that the embryo develops in the capitate 

 end of the egg, and while the larva is white at first, or of the 

 exact color of the young ovule, it becomes slightly greenish or 

 roseate when full grown, which is in about a 

 month, or coincident with the ri-pening of the 

 seed. It perforates the capsule and drops to 

 the ground, having six thoracic legs, which 

 doubtless aid it at this period of its life. It 

 remains through the fall, winter, and early 

 spring months in a tough cocoon, transforms 

 to the chrysalis state about a week before the 

 Yuccas bloom again, and finally issues as a 

 moth to continue the annual cycle of its career. 

 The chr^'salis (Fig. 8) has a capitate spine 

 and a series of dorsal spines, some of whicli are 

 spatulate and admirably fitted for helping it to work through 

 the ground. 



" The effect of the puncture of the female moth on the fruit is 

 at once noticeable by a darker green discoloration externally. 

 In time this becomes a depression, causing a constriction of the 

 pod, and the irregularities of the })od (Fig. 9, />, c"), which have 

 been supposed to be characteristic of the genus Yucca, are really 

 due to these punctures, which ordinarily occur just l)elow the 

 middle." The absolute need of Pronulia in the pollination of our 

 deniscent Yuccas I have proved over and over again, in many 



Fig. S. — PiiuNuiJ.v 

 yiccASEi.LA : I, male ; 

 m, female chrysalis. 



