It were out of place to recall my long relations with the bolete and the agaric if the insect did not here enter into a question of grave interest. Several mushrooms are edible, some even enjoy a great reputation; others are formidable poisons. Short of botanical studies that are not within everybody's reach, how are we to distinguish the harmless from the venomous? There is a widespread belief which says that any mushroom which insects, or, more frequently, their larvae, their grubs, accept can be accepted without fear; any mushroom which they refuse must be refused. What is wholesome food for them cannot fail to be the same for us; what is poisonous to them is bound to be equally baneful to ourselves. This is how people argue, with apparent logic, but without reflecting upon the very different capabilities of stomachs in the matter of diet. After all, may there not be some justification for the belief? That is what I purpose examining.