. Bulletin / Division of Entomology, Bureau of Sugar Experiment Stations, Queensland. fungus, and one of bacteria. 27th August—Four grubs dead of fungus ; only two left alive. 30th August—The last two grubs were dead of fungus. Concusions.—From the above experiments, it was quite evidentthat low temperature and abundant moisture are most important factorsin the virulence of these diseases. The bacterial contagion was far lessdestructive than Muscardine fungus, under the same conditions. Never-theless, as noted above, these two diseases often go hand in hand, thcrgrubs dying by a complication o
. Bulletin / Division of Entomology, Bureau of Sugar Experiment Stations, Queensland. fungus, and one of bacteria. 27th August—Four grubs dead of fungus ; only two left alive. 30th August—The last two grubs were dead of fungus. Concusions.—From the above experiments, it was quite evidentthat low temperature and abundant moisture are most important factorsin the virulence of these diseases. The bacterial contagion was far lessdestructive than Muscardine fungus, under the same conditions. Never-theless, as noted above, these two diseases often go hand in hand, thcrgrubs dying by a complication of ailments. Often the legs of a grubbecame blackened, one or more falling off—unmistakable^ sym])t()ms ofthe bacterial complaint—then the grub would (]ui(kly succumb to thefungus, his body becoming hard and cheesy, and, linally. turning greenas the spores develojoed. The fungus spores are exceedingly small ;even when viewed under a microscope with a magniiication oF 400 dia-meters, they appear as exceedingly tiny oval bodies (Fig. 5). Oidinariiy, CONTEOL FOK WHITE GEUBS. Fig. 5.—Microscopic characters of the Muscardine fungus; magnified about 800 Mature sjDores. 2. Spores gernainating. 3. Mycehum, the vegetativestructure, which finally forms a compact white mat ; the viltimate tips onthe surface are the sporophores (spore-bearers). 4. Sporophores, showinghow the mycelium becomes constricted at the tips like strings of sausages,forming the sjDores. These drop off as they ripen; the green powder onthe dead grub is composed of myriads oi them. 18 A STUDY OF XATURAT^ :\I KTTIODS OF unless broken apart, they are attached end to end, like a string of sausages,,for these fruiting bodies are formed from the branching tubes of themycelium (the vegetative part of the mould). Wherever the myceliumcomes to the surface of the dead grub, it branches profuseh, and each ofthe tips then becomes constricted into a line oi numerous spores. Hence,the numbers produced by a
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