168 FRUIT INSECTS 



of minute Hymenoptera are true parasites of the scale in 

 America : Aphelinus fascipennis and mytilaspidis, Aspidioti- 

 phagus citrinus, Anaphes gracilis, Physcus varicornis, Prospal- 

 tella aurantii, P. pernidosi, Ahlerus disiocampcE and Rhopoidens 

 dtrinus. Most of these parasites are widely distributed in the 

 United States and other countries, and they are all general 

 feeders on other species of the armored scales. Sometimes these 

 parasites destroy enormous numbers of the scales, and they will 

 always be very potent factors in Nature's efforts to help man 

 in controlling this pest. 



About a dozen ladybird beetles have been found eating the 

 San Jose scale in America. The most important and useful 

 of these are the twice-stabbed ladybird, Chilocorus hivulnerus, 

 the tiny black Microweisea niisella, another tiny, dark, wine-red 

 colored species of the same genus, M. suturalis, and a Malachiid 

 beetle, Collops quadrimaculatus. The most useful and inter- 

 esting of these is the tiny black misella, which is widely dis- 

 tributed in the United States. The little beetles stand astride 

 the full-grown female scales, push their heads under the margin 

 of the scale and devour the soft, yellow insect beneath. The 

 grubs of the beetle feed upon the smaller scales. The chief 

 natural enemy which kept this scale in check in its native home 

 in China was found to be a ladybird beetle, Chilocorus similis, 

 which is almost identical in the beetle stage to our native Ameri- 

 can twice-stabbed ladybird, but differs in the reddish color of 

 the grub and it also breeds much faster. This Asiatic ladybird 

 beetle was introduced into the United States and readily 

 attacked the scale, multiplied rapidly at Washington, and was 

 sent into other localities both North and South. Lack of food 

 and a native parasite destroyed the Washington colony and the 

 insect failed to thrive in the North. It bred in great numbers 

 for a time in Georgia, but man's spraying operations soon cut 

 off its food supply and it was nearly exterminated. 



Several fungous and other diseases sometimes attack the San 



