Survey on the soil predaceous prostigmatid mites indicated the occurrence of 12 species. These were six from Cunaxidae and three from each Cheyletidae and Bdellidae. Population dynamics for a whole year showed that Gunaxids and Cheyletids increased in numbers during spring and summer while decreased in cold months of winter. On the contrary Bdellid population flourished in autumn and winter and decreased in summer. Zusammenfassung Zur Populationsdynamik einiger räuberischer Bodenmilben der Gruppe Prostigmata in Ägypten Bei Bodenuntersuchungen auf dem Gelände der Farmen der Landw. Fakultät in Giza wurden in der Streu unter Sträuchern und Bäumen 12 prostigmate Milbenarten: 6 aus der Familie Cunaxidae und je 3 aus den Familien Cheyletidae und Bdellidae gefunden. Ein Jahr lang durchgeführte Populationsstudien zeigten, daß die Individuenzahl der Cunaxidae und Cheyletidae während des Frühjahrs und Sommers anstieg und in der kälteren Jahreszeit absank. Im Gegenteil hierzu zeigten die Bdellidae im Herbst und Winter die größte Populationsdichte und im Sommer die geringste.

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Cunaxa capreolus BERLESE failed to develop on diets of plant material but developed equally well on diets of booklice (Psocoptera) or of the citrus brown mite, Eutetranychus orientalis (KLEIN), which were eaten in their active stages and not as eggs. Cannibalism occurred during shortage of food. Although the growth of the immature stages of C. capreolus was accompanied by an increasing consumption of prey, yet their total consumption was less than 30 ~ of that of the female adult. The number of prey individuals consumed by C. capreolus was inversely related to temperature but consumption rate increased slightly with increasing temperature.The feeding habits of the cunaxid mites and their role in biological control have not been fully investigated. The mites are cosmopolitan and free livings; some inhabit trees but most are associated with fallen leaves and top soil layers (LORD, 1949; MEYER & RYKE, 1959;MUMA, 1960 MUMA, , 1965 ZAHER et al. 1970, RASMY et al., 1972.During work on predaceous prostigmatid mites in litter under shrubs and trees in Giza ;Cunaxa capreolus BERLESE was the dominant species, but in Florida MUMA (1965) found this mite inhabiting citrus trees. The food preference of C. capreolus has therefore been investigated and special attention has been paid to the effect of temperature on the amount of food consumed. MATERIALS AND METHODSThe food preference and capacity of C. capreolus and the effect of food type on its development were studied using two animal diets : booklice (Psocoptera) and the citrus brown mite Eutetranychus orientalis (KLEIN) and three plant diets: date palm pollen, and slices of potato, alone or in diluted yeast solution. For each treatment about 35 newly hatched larvae of C. capreolus were confined singly in glass rings of 1 cm diameter and 7 mm deep. The rings were fixed to glass slides and each was covered with another glass slide held in position with rubber bands. When the young reached maturity the sexes were allowed to mate and the females were retained to complete their oviposition. The food preference experiments were carried out at 30~ 4-1 ~ and those on feeding capacity at 15, 20, 25 and 30~ 4-1 ~ respectively. RESULTS FEEDING HABITS AND BEHAVIOLIRWhen supplied with any of the plant diets C. capreolus failed to develop and reproduce and died within few days. It developed and reproduced on either of the animal

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Macrocheles matrius (Hull) was found in great numbers and fed variously on house fly eggs and larvae during its different stages except larvae which proved to be unfeeding stage. The female of this species consumed an average of 12.9 and 118.4 eggs during immature stages and adult stages respectively. Feeding on house fly eggs increased the female predator fecundity and prolonged oviposition period. The number of deposited eggs per female averaged 63.8 and 40.7 eggs when fed on house fly eggs and larvae respectively. Generation period (from egg to egg) averaged 4.9 and 6.0 days when fed on house fly eggs and larvae respectively. Zusammenfassung Zur Biologie und räuberischen Effektivität von Macrocheles matrius (Hull) (Acari, Mesostigmata) Die Milbe Macrocheles matrius wurde in großer Zahl als Räuber von Hausfliegen‐Eiern und ‐Larven festgestellt. Alle fressenden Stadien der Milbe lebten auf diese Weise räuberisch. Eine weibliche Milbe verzehrte während ihrer Larvenentwicklung 12,9 und als reifes Tier 118,4 Fliegeneier im Durchschnitt. Der Fraß an Hausfliegeneiern erhöhte die Fekundität des Milbenweibchens und verlängerte die Ovipositions‐Periode. Die Zahl abgelegter Eier pro Weibchen betrug im Mittel 63,8 nach Fraß von Eiern bzw. 40,7 nach Fraß von Larven der Stubenfliege. Die Generation von Ei zu Ei dauerte im Mittel nur 4,9 Tage bei Ernährung von Eiern bzw. 6,0 Tage bei Ernährung mit Larven der Stubenfliege.