THE MONTHLY BULLETIN. 109 



of mealybugs during the past few seasons have been closely connected 

 with infestations of ants, and particularly the introduced Argentine ant. 

 Careful field observations revealed the fact that the ants were not only 

 instrumental in distributing the mealybugs upon the trees and through 

 the orchards, but that they actually protect these by keeping the natural 

 enemies away from the pest. His observations led him to believe that 

 if the ants could be kept from the trees, the insect enemies of- the mealy- 

 bug might be able to keep them down to harmless numbers. A series 

 of experiments were instituted, some on large orchard scale, and it was 

 found that so far as the citrus mealybug was concerned banding the 

 trees with tanglefoot and thus keeping them free from ants was all that 

 was required to control the pest. In fact, Mr. Woglum has given us 

 some remarkable orchard demonstrations of the effectiveness of this 

 method of control, and the importance of his work to the citrus growers 

 of California can not be overestimated. 



In Mr. Woglum 's recommendations it is suggested that the Insectary 

 be asked to supply the requisite natural enemies for placing in the 

 orchard after the trees have been banded and the worst infestations 

 reduced by spraying with water. This we are preparing to do and the 

 laboratory for this" purpose will be established at Alhambra during 

 March of the present year. The mealybugs have a large number of 

 insect enemies, some introduced and others native to California, which 

 will be useful in this work. These may be divided into two groups, 

 according to habits : The predators which in the larval and sometimes 

 in the adult stages devour large numbers of the eggs and young mealy- 

 bugs, and the parasites which destroy their host by depositing an egg 

 within its body, the egg producing a maggot which feeds upon the 

 internal organs finally killing the mealybug and emerging as a winged 

 adult insect ready to begin another generation. 



PREDACIOUS INSECTS. 

 The Brown Lacewing (Sympherobius Californicus Banks). 



This insect is generally recognized as the most important natural 

 enemy of the mealybugs and occurs commonly in the mealybug-infested 

 sections of the South. The adult insect is of a grayish-brown color, with 

 markings of a darker shade of brown on the wings. It is slightly over 

 one-half inch in length. The eggs are white in color and are deposited 

 in the vicinity of mealybugs on the leaves and fruit. Clausen states 

 that he has seen the eggs deposited upon the mealybug itself at times 

 and also within the egg masses. The larvae are extremely voracious 

 and destroy the host insect in large numbers. The adult also feeds 

 upon the smaller mealybugs to some extent. It is a general feeder, 

 and all kinds of mealybugs are subject to its attack. The cocoon 

 is silken, oblong-oval in shape and dirty white or gray in color. It is 

 placed in a protected position, generally under the loose bark and fre- 

 quent ly in large clusters. This very beneficial insect would be even 

 more valuable were it not for the fact that it has its own insect enemies 

 which al times become very ;ibundant. Among these are a species of 

 Pachym won, another Pteromalid, having a long ovipositor, and a par- 

 asitic Cynipid. I have net reared Isodromus iceryce from this host, 

 but Clausen and Bssig both record it as an important enemy of this 

 valuable predator. 



