Pollination and Oviposition. 87 



rule, is accomplished in some other flower than that from which 

 the pollen was gathered, and that cross-fertilization is thus se- 

 cured. 



" Once fully equipped with this important commodity, she 

 may be seen either crawling over or resting within the flower, 

 generally with the head toward the base. From time to time 

 she makes a sudden dart and deftly runs around the stamens, 

 and anon takes a position with the body between and the legs 

 straddling two of them, her head being usually turned toward 

 the stigma. As the terminal portion of the stamens is always 

 more or less recurved, she generally has to retreat between two 

 of them until the tip of her abdomen can reach the pistil. As 



. FIG. 3. Flower of Yucca jilamcntosa with near petals removed, showing Pronuha in 

 act of ovipositing. 



soon as a favorable point is reached, generally just below .the 

 middle, she rests motionless for a short time, when the abdomen 

 is slightly raised and the lance-like ovipositor is thrust into the 

 soft tissue, held there the best part of a minute, while the egg is 

 conducted to its destination, and then withdrawn by a series of 

 up-and-down motions. 



" In non-technical language, the pistil or the young fruit, be- 

 low the stigmatic tube, shows externally at this time six quite 

 distinct longitudinal divisions, each having a median ridge, there 

 being six corresponding depressions or concavities in which the 

 six stamens fit, especially at the base. Technically, the pistil is 

 a three-celled ovary, the styles bifid at tip and united so as to 



