BENEFICIAL INSECTS 



615 



sectary requesting that a colony of Aus- 

 tralian ladybirds be sent to him to check 

 the threatened outbreak of the pest. 



Encouraged by the success of this first 

 undertaking, the work has been success- 

 fully prosecuted for many years, until to- 

 day California has the largest insectary 

 in the world devoted exclusively to the 

 introduction, propagation and dissemina- 

 tion of beneficial insects. 



By careful study it has been determined 

 that, in a majority of cases, what in Cal- 

 ifornia is termed an "insect pest" Is 

 usually a foreign destructive insect that 

 has been accidentally introduced into the 

 state without its natural Insect check 

 (who used It not only for food for itself. 

 but upon which to feed and propagate 

 its young). 



The introduced species increases enor- 

 mously and in a remarkably short time, 

 by sheer force of numbers, becomes what 

 we term "an insect pest." 



From the above statement the work of 

 the state Insectary can be easily under- 

 stood. Its first duty is to locate the home 

 of the natural insect enemy, which is 

 usually the country from which the pest 

 was introduced. The beneficial form is 

 then sent to the Insectary, either through 

 correspondence with some foreign ento- 

 mologist or by sending our entomological 

 explorer direct to that country. 



After receipt at the Insectary several 

 generations must be bred in confinement 

 in order to segregate the secondary and 

 even tertiary forms before any adults of 

 the species desired may be liberated in 

 the open. 



Fig. 1. Field Agents with 300 Pounds of 

 Lad.vbirds In sacks at a pack train station. 

 Sacks are only half filled to allow the beetles 

 to move slightl.T and to avoid crushing when 

 packed on the mules. Sieves, pans, brushes 

 and sacks used for this collecting are hanging 

 on the fence. 



Fig. 2. The Vedalia (Novius cardinalis Muls). 

 Slightly less than one-quarter of an inch in 

 length and oval in shape. The color pat- 

 tern is very pronounced and striking, being 

 red and black. In the females red predomi- 

 nates while in the males there is mure 

 black. The larvae are often over one-half 

 of an inch long and lead-gray in color with 

 reddish sides. They are often covered with 

 whitish nowder from the egg sacs of the 

 cottony cushion scale. The eggs are a little 

 larger than those of Novius koebelei. but are 

 the same color and laid in similar places. 

 The young feed upon the eggs and young 

 scales and do great execution. The great 

 pi-olificness and appetite of this species 

 enables it to do what no other predator has 

 yet done. It disappears with the host and 

 IS constantly being sent out by the State 

 Insectary. Introduced in California by Al- 

 bert Koebele. It feeds entirely upoii the 

 eggs and young of the cottmy cushion scale 

 ilcenia ptirchaxi). To this beetle is ac- 

 credited the salvation of the citrus industry 

 in California, which was threatened with 

 destruction by the above scale. 



To this part of the work too much care 

 cannot be given, as the success or failure 

 of the entire undertaking hinges on the 

 careful segregation of the species at this 

 point. 



To successfully establish an introduced 

 species, several additional importations 

 must be made and adults liberated as in 

 many species if but a single introduction 

 is made, in-breeding after a remarkably 

 few generations will not only dwarf the 

 species but actually stop reproduction. 



Many failures to establish foreign spe- 

 cies during the past is directly traceable 

 to this very important feature, owing to 

 lack of sufficient knowledge on the part 

 of the collector who has been content with 

 but a single introduction. This is espe- 

 cially true of the Coccinellidae (Lady- 

 bird) family. 



We find then the main essential factors 

 toward successful foreign introductions 



