INSECT PARASITES AXD PREDATORS OF IXSECT PESTS 5 



onies have been seen early in July massed upon rocks near streams 

 and in bright sunlight, and in these instances the temperature of 

 the rocks was certainly above 100° F. 



A considerable number of species of ladybird beetles feed upon 

 mealybugs, and the larvae of many of them bear a whitish waxy 

 coating that gives them a resemblance to the insects upon which they 

 feed. A few of the species that attack aphids, scale insects, and 

 white flies also bear a similar covering. 



One of the most effective of these beetles is the so-called "Austra- 

 lian ladybird beetle " (Crypt olaemus montrouzieri Muls.) which was 

 imported into California from Australia in 1891-92 for the control 

 of mealybugs attacking citrus in that State. Its life history differs 

 from that of Hippodamia convergent in that the eggs are laid singly 

 among the mealybugs, rather than in clusters, and the winter is 

 passed in the resting stage in curled leaves and rubbish beneath 

 the trees. This method of hibernation is a decided disadvantage 

 to the species under the conditions existing in this country, as the 

 fallen leaves decay, are blown awa}^, or are plowed under during 

 the winter. As a result, relatively few of the insects survive until 

 the following spring. Because of this, the mealybugs are able to 

 get a good start and become very abundant and injurious before 

 the beetle is able to increase sufficiently to cope with them. This 

 difficulty was overcome by the development, by the California State 

 Department of Agriculture and the agricultural experiment station, 

 of rearing methods whereby millions of the beetles could be pro- 

 duced at relatively low cost and liberated in infested citrus groves 

 early each season. Effective control was thus obtained sufficiently 

 early so that little or no damage was done by the mealybugs. 



Another imported ladybird beetle of great value is the far-famed 

 vedalia beetle (Rodol'm cardinal Is Muls.) (fig. 2), which, as previ- 

 ously mentioned, was imported into California from Australia in 

 1888-89 for the control of the destructive cottony-cushion scale 

 (I eery a purchasi Mask.) on citrus. So rapidly did this beetle in- 

 crease that within a few years this destructive scale ceased to be a 

 pest, and to the present day it is of little or no consequence in the 

 citrus groves. Occasionally a small infestation may appear, but this 

 may be quickly eliminated by the liberation of colonies of the beetle. 

 Usually, however, the beetles appear of their own accord. Follow- 

 ing this remarkable success, the beetle was introduced into many 

 other countries in which the cottony-cushion scale had become estab- 

 lished, and in nearly every instance similar striking results were 

 obtained. 



Another importation from abroad is the Chinese ladybird beetle 

 (Chilocoinbs similis Rossi), which was brought from Asia for use 

 against the San Jose scale (Aspidiotus pemiciosus Comst.). It was 

 found in the orchards for a number of years after liberation but 

 apparently did not become established. The adult beetles are shiny 

 black and bear one red spot on the center of each wing cover, thus 

 greatly resembling the twice-stabbed ladybird beetle (Chilocorus 

 oivulnerus Muls.) , which is native to this country and also feeds upon 

 scale insects. The eggs are deposited singly among the scales or 

 beneath the scale covering. The spiny larvae chew holes through 

 the covers of large numbers of scales and feed upon the developing 



