55 



very l;irjj;o nuinlxT (if dead flien were found under tlu^ hIicIIh of black ncalc, more so 

 than duriiij; any otlier time of tliis investi<j;ation. ('ause unknown to me. 



Fehruftry. — The hirva and pupa of the insect in question were rarely found during 

 the weekly investigations of this montli. Flies were abundant upon tlie foliage of 

 citrus trees and upon the stenis of chili peppers during most of the bright sunny 

 days of the past month. The mortality of adult flies under the scale continues, but 

 not so apparently as during January. 



" Length of time of a generation under natural conditions." I have but one posi- 

 tive record of this. On August 14, 1903, I liberate<l a colony of *S'. njaneit (Hies) on 

 the premises of G. A. Lindsay, Long Beach. No Scutellista had l)een placed previous 

 to this nearer than 4 miles away. I was in a j)Osition to watch the progress of this 

 colony closely. I soon saw by the color and appearance of the scale {L. oleiav) that 

 they were parasitized. On October 8, 1903, I was investigating the j)rogress of the 

 parasites and upon removing a full-grown black scale, a fully developed Scutellista 

 emerged from the shell into my hands. This makes Hfty-tive days from the time the 

 flies were liberated and the first ai)pearance of the adult of the next generation. 



On October 18, 1903, I found a large quantity of horseweeds in a gulch to leeward 

 of a lemon orchard in which S. cyanea had been placed. These were found to be 

 covered with black scale {L. oleax) . Upon investigation it was ff)und that the scale 

 was extensively i)arasitized, at least 50 per cent; ui)on a ))iece of horseweed 1(5 inches 

 long I removed 80 ))lack scale; 42 of these contained parasites, the majority being 

 8. cyanen. 



On October 19 I cut these weeds into short lengths, placed them in fruit jars, 

 covered the tops with lawn and distril)uted them in the different citrus orchards. 

 The owners agreeing to liberate such flies as emerged once every twenty-four hours. 

 On De{;ember 18 flies were still issuing from the weeds i)la(!ed in one of these jars. 

 Later on this jar was removed to the oflice in Los Angeles, and the commissioners 

 informed me that flies {S. cyanea) continued to emerge up to the ninety-seventh day 

 after being placed in the jar. These weeds were mature when placed in jar, and the 

 scale upon them was fully developed. 



Tlic points of greatest interest shown in the notes al)ove quoted are 

 that at tlie height of the l)reedino- season (in August and Septeinher) 

 the life cycle of this insect is about iifty-tive days, and that during the 

 colder season of winter these insects, as already indicated in my own 

 notes, enter a period of seniihilx'rnation wliich may extend over a 

 period of three months. The l)earing of these facts on the usefidness 

 of this parasite is very apparent. The feature of greatest anxiety was 

 how it would pass the winter season during which, in the case of many 

 citrus groves at least, there would he no food foi them. This problem 

 seems to be solved by the hibernation of the insect, which l)ridges very 

 nicely the period referred to. On the other hand, it is shown that 

 where conditions are favorable — that is, in sunny situations and where 

 the food supply exists due to the same conditions, activity continues 

 throughout the winter. There seems to be no possi])le n^ason for 

 doubting, therefore, the full establishment of this insect in southern 

 California and its present and prospective great usefulness. 



Scutellista cyanea^ of which such good showing is now made, as 

 pointed out by Doctor Howard, is prol)al)ly of Oriental origin, having 

 first b<H>n descrilxnl l)}^ Motschulsk}', from Ceylon, from which place 



