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In the “uneven hatch” areas secondary parasitism has precluded Aphycus lounsburyi How. becoming, by itself, an adequate means of control of black scale, except, possibly, at irregular intervals. Eight hyperparasites are known to attack Aphycus and three others arc under suspicion. It is, however, of much value in the uneven-hatch areas as an aid to fumigation by evening up the hatch. In the interior or “even-hatch” areas, low temperatures which. cause retarded development of Aphycus, particularly in the pupal stage, during the one short period when it might alone control the scale, prevents its doing so. Aphycus, with Scutellista cyanea and Rhizobius ventralis, completes a sequence of enemies attacking the black scale and this fact offers a possibility of control. The distribution of Aphycus Lounsburyi has been so complete, both with and without human agency that it is safe to say there is hardly a citrus orchard, or for that matter a planting of ornamentals or growth of native shrubbery in Southern California, infested with black scale, in which it is not possible to find Aphycus or evidence of its work. In spite of the many factors operating to its disadvantage it is without question a most valuable addition to the parasite fauna of California.

Temperature influences the reproductive capacity of the Saissetia coffeae and its parasitoid. The lowering of temperatures increased the egg production of the scales. The high temperature (30°C) reduced the egg-laying of Metaphycus helvolus and resulted in a greater proportion of male progenies. However, oviposition and sex ratio of Scutellista cyanea were unaffected by high temperature. The high temperature too, accelerated the development of ovarian eggs of both parasitoids.