312 



far found them only npon the leaves, the juice of which serves them as 

 food. The first of these is a small brown Capsid kuowu as RaUicotoma 

 ralida: the second, a curious Homopterous insect. Ticida cingulaia. of 

 a brownish color, banded with white: the third and last is a Coccid. 

 Fseudococcus yuccce, having the general asi)ect of the common mealy- 

 bug of our hothouses. 



Certain other kinds of insects, notably locusts, are occasionally found 

 among the leaves of this Yucca, but as they have not been observed to 

 feed upon this plant, their piesence uidou it appears to have been puj?ely 

 accidental, and not for the purpose of obtaining food. 



The tbllowiug is a list of the insects that I have observed within or 

 among the llowers of Yucca icliipplei: 



Coleoptera— Conrinued, 



Hynieiiopt^ra : Rippodamia convergens. 



Plalylabus sj). f Anthon<Tus afjaren-fis. 



Lepidoptera : Carpoplt ilus paUipen n is. 



Lapjlujgma frugiperda. Acukfojjs falsa. 



Pronuha maculata. Diahrotica soror, 



Prodoxns margiuaius. Diabrotica trivittata. 



Prodoxas anescens. ITemipTera : 



Diptera: Aphis sp.f 



Genus? Species? Family Geomy- Tliamnoteitij' scnitUaia. 



zida?. Xeuroptera: 



Coleoptera: Chrysopa sp.f 



Aleochara sj). f 



Of these, the Lajjliyfjina was present in three exami)les, but only at 

 night, and may have been attracted by the light from my lantern, since 

 they did not attempt to feed u^^on the flowers. Diahrotica soror was 

 observed to feed upon the pollen-masses as well as upon the perianth. 

 The Aphids ^ere congregated upon the outside of the flowers. I did 

 not observe a single butterfly or wild bee of any kind visit these 

 flowers, although all of these insects were cpiite abuudant in the ^^icinity 

 where these observations were made. And the same observation also 

 applies to humming-birds. Pronuha maculata and the two species of 

 Prodoxns were present during the month of June and a portion of May 

 and July : but none were observed after the 24th of July. The Prodoxus 

 moths usually rested upon the inside of the perianth, but the favorite 

 position of the Fronuha was resting upon the side of the ovary, her 

 head turned toward but not reaching the stigma. 



In 1892, at the request of Dr. Edey. I paid particular attention to the 

 I)ollination of this Yucca and the actions of Pronuha maculata. After 

 repeated watchings. both during the daytime and at night by the aid 

 of a lantern. I was fortunate enough to witness the process of egg-depos- 

 iting and pollinating. This was on the 12th of Jime of the present year. 

 The sun was only about tbrty minutes high, but was shining brightly, 

 and a cool breeze was blowing at the time. The Yucca plant was about 

 eight feet high, and the flowers in the lower three-fifths of the panicle 



