In 1960 and 1961, studies were made on Pseudometagea schwarzii (Ashm.), a parasite of Lasius neoniger Emery in southern Ontario. The eggs are deposited in vegetation surrounding the ant nest and the first instar larvae (planidia) transfer to the ant Larvae by attaching themselves to the worker ants. The larvae overwinter as internal parasites but complete their development as external parasites after the host has pupated in the spring. The adults emerge in June and oviposit immediately.The adult parasites usually do not leave the area of the nest and, through the foraging activities of the ants, the planidia are returned to the colony that was originally parasitized. Hence the population is intensified and localized. Ninety percent parasitism of the overwintering brood may occur. The possible effects of this parasite on the host population are discussed.

Results of the analyses for digestive enzymes in the glands and midguts of five species of ants showed that invertase is usually secreted by the maxillary glands, amylase by the salivary glands, and protease and lipase by the midgut. Lipase was found in the post-pharyngeal glands but observations indicate that it is not associated with the digestion of ingested food. Differences in the activity of the enzymes in different species tended to reflect the feeding habits of the ants.

Results of analyses for digestive enzymes in the glands and midgut of Camponotus herculeanus (L.) indicate that carbohydrases are associated with the foregut, and lipases and proteinases are confined to the midgut. As the content of the crop can be regurgitated, carbohydrate digestion may occur extra-orally. The worker ants cannot ingest solid particles and, because the brood is fed on regurgitated food, the entire protein requirements of a colony are apparently supplied by the haemolymph and water-soluble protein of the prey. WHEELER (1910) and WHEELER t~ BAILEY (1920) summarized the types of food of ants and gave detailed accounts of some of the more specialized diets. Little seems to be known, however, about ingestion and digestion, particularly of protein food, by worker ants. EISNER (1957) stated that the complete loss of portal mobility of the proventricull of the Dolichoderinae and Formicinae would probably prevent the transfer of any but the most minute food particles from the foregut to the midgut. More recent studies (EISNER & HAPP, 1962) showed that solid particles over 100 # in diameter are prevented from reaching the foregut of Camponotus pennsylvanicus (De Geer) by the filtering action of the mouth parts and infrabuccal cavity. Moreover, particles as small as 10 ~ in diameter, though they may initially reach the crop, are eventually filtered from .the liquid crop coment by regurgitative feeding among the worker ants. These findings raise the questions of whether predacious Formicinae can utilize only the haemolymph of their prey or whether extra-midgut digestion occurs. In this investigation some of the digestive enzymes present in Camponotus herculeanus (L.) were determined and the possibilities of extra-midgut and extra-oral digestion investigated. METHODS AND MATERIALSInitial work consisted of observing the attack and subsequent feeding behaviour of workers of C. herculeanus on larvae of Musca domestica L. Before the prey were introduced into the observation area, amaranth red dye dissolved in a sugar solution was fed to the workers. This aided in observing regurgkated crop content during feeding activities.

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Phytophagous orchard mites have become so troublesome in British Columhia during the last decade that special attention has been given to studies on their ecology and control. An iniportant rerequisite for such studies is an accurate and rapid method of estimating popn I ' ation densities of both the mites and their