150 PROCEEDINGS OP THIRTY-THIRD FRUIT-GROWERS ' CONVENTION. 



host, a cabbage plusia, one of the cut-worms, over 2,500 individual para- 

 sites were reared. In our own State we find that the Corny s fusca, the 

 parasite of the apricot scale, has parasitized from 85 to 95 per cent 

 of the scales in some of the infested orchards. 



Many of the parasites have different habits; some attack the eggs 

 of insects, some the larvae, some the pupae, and some species carry off 

 the adults and store them in well-prepared nests, where, when sufficient 

 food has been provided for the offspring, the egg is laid among the 

 stored individuals. Probably the most interesting workers, and those 

 which do not seem to mind the close observer, are the aphis parasites, 

 the Braconids. It is a most wonderful study for any lover of nature 

 to observe these little parasites make an attack on a plant louse. They 

 are ever on the move and seem to be able to tell whether the aphis has 

 been already attacked. When this is decided, the Braconid brings its 

 abdomen under its thorax, takes aim at the aphis, and with a sudden, 

 quick motion, thrusts its egg into the body of the host-to-be, and is then 

 ready for another. Many of you have noticed the dead, light-brown, 

 swollen bodies of plant lice on the leaves of the cabbage and other 

 plants. These contain parasites and, if closely watched, one will soon 

 notice a small hole in the body of the louse. This is the exit hole from 

 which the parasite has escaped. 



Some of our common caterpillars are attacked by ichneumons, and we 

 find that after spinning the cocoon they remain unchanged instead of 

 continuing their metamorphosis and there appear a number of smaller 

 cocoons, which in time produce the adult ichneumon parasites. 



Among the Diptera, the true flies, we have the tachnids, which are 

 true internal parasites. The adult deposits its eggs on the caterpillar 

 and the young maggot when hatched enters the body and begins to feed. 

 The victim soon looks sickly and is hardly able to spin a cocoon. After 

 completely devouring the contents of the host, the larvse, for there are 

 generally several, are full grown and work their way out of the body 

 wall and fall to the ground, where they pupate and remain during the 

 winter. 



As stated above, the beginning of insect parasitism in California 

 started in the year 1888, when, disheartened by enormous expenses and 

 the great reduction of crops, the growers caused the search to be made 

 for the natural enemy of the cottony cushion scale, which resulted so 

 successfully and made Vedalia the shibboleth of insect parasitism. 

 Unfortunately, this ladybird feeds only on the cottony cushion scale,, 

 and we had to search for other species to help reduce our other pests. 

 We soon received, through the diligent search of our collector, many 

 species of ladybirds, some of which proved a great help toward the 

 reduction of our insect enemies. One species, in particular, which has 

 done much to reduce the olive scale in several coast counties, is the 



