The citrophilus mealybug (Pseudococcus gahani Green) first found in the citrus orchards of Southern California at Uplands, San Bernardino County in 1913, is now established in all of the southern citrus producing counties with the exception of San Diego and Imperial. In Los Angeles, Orange, San Bernardino and Riverside Counties, it occurs over a rather large acreage. In Ventura and Santa Barbara Counties the infestations are new and as yet are confined to a limited acreage though none the less severe in degree of infestation. Due to adverse climatic conditions this species of mealybug has proven less serious in the interior counties as San Bernardino and Riverside and while the spread has continued the infestations have been exceedingly light since the date of the original outbreak. In the coast counties the spread has been rapid and the infestations as a whole very heavy. The citrophilus mealybug is particularly resistant to fumigation and has the usual resistance of this group of insects to sprays. Water under pressure during the peak of oviposition period in the spring is by far the most successful means of mechanical control. Natural enemies of which there are several native species present in the orchards are an important factor of control. The ladybird beetle, Cryptolaemus montrouzieri Muls., an introduced predator, is particularly effective. Eight county and Association insectaries in Southern California are producing and liberating monthly over half a million of these beetles, throughout the infested areas of Southern California. Where they are made available in quantity early in the year they are being used successfully as a control measure.