PROCEEDINGS OF THIRTY-THIRD FRUIT-GROWERS ' CONVENTION. 149 



aroused the scientific world, and all eyes were turned toward California, 

 for it was she who, after spending hundreds of thousands of dollars, 

 had conquered a terrible pest, which threatened to destroy her citrus 

 industry, producing to-day over $30,000,000 annually. 



Having succeeded with this remarkable experiment and finding our- 

 selves interested in this work, we continued the search for enemies of 

 our various other pests, since which time several expeditions have been 

 undertaken in the endeavor to find, first the home of the pest and then 

 the true parasite of it. 



It is a well-known fact that all insects have certain enemies which 

 prey upon them, either predaceous (those which live externally and 

 generally devour the host), or parasitic (those which are generally 

 found inclosed in the body of the insect or in its covering.) Of the first 

 class we have a host of individuals in the various orders. Paramount 

 among these are the ladybirds (Coccinellidae), to which belongs the 

 Vedalia carclinalis, and which are the important enemies of plant lice 

 and scale insects. Among other orders we have the larvae and adults 

 of many beetles, the larvae of the lace-wing flies, and those of the 

 Diptera, the syrphus flies. All these attack other insects, each select- 

 ing the particular family it can master, the Carabid beetle anxious to 

 devour the large cut-worm, the lace-wing and the syrphus flies ever 

 ready to suck the juices of the tender plant lice. They all have their 

 favorites and all are hearty eaters. Whenever a pest becomes abundant 

 it at once means that some favorable condition for the propagation of 

 its enemies is at hand. These shortly appear on the scene, and although 

 at first few in number, soon deposit eggs, which quickly hatch into 

 larvae, some of which are very minute and are often overlooked; these 

 begin to feed, molting at intervals, and we soon notice the very odd 

 but striking forms of the pupae resting on the leaves, the battlefield as 

 it were, surrounded by the empty skins of the pest. In a short time 

 there appears from the pupa the adult, which continues the good work 

 as did the last generation. 



The parasitic insects include the great orders of Hymenoptera and 

 Diptera. The first contains probably the greatest number of true 

 parasites and presents without question the most remarkable phases of 

 insect parasitism. Eoughly speaking there are about 30,000 Hymenop- 

 tera described. Probably this number could be greatly enlarged, and 

 no doubt will be, as there are discovered every year many species which 

 are new to science. We shall no doubt be able to multiply the present 

 number by ten, and this will give a rough estimate of what we may 

 expect in the parasitic group. It is in this order that we hope for 

 great relief in insect parasitism. 



Some of the smaller species of ichneumons and chalcid flies are very 

 prolific, and among the records we can find instances where, from one 



