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Rh affirming that they never witnessed this phenomenon in any other insects except certain species of Lampyris and Elater. Certain writers of older date, however, affirm that they have, and it is difficult to determine the fact amidst such conflicting evidence. Still, however, when we consider Madam Merian's circumstantial statement, and how improbable it is, notwithstanding the grave errors into which she occasionally falls, that she could be mistaken in a matter so obvious, while, at the same time, she could have no motive intentionally to mislead—that the natives affirm they have sometimes seen it luminous—and that the names given to the insect, both by the colonists and natives, such as Lantarendrager, Porte-Lanterne, mouche à feu, all bear allusion to this property—it may be concluded, that the opinion generally received is nearest the truth. It should be kept in mind that all the negative evidence merely proves that the light is seldom exhibited, while the testimony of a single trustworthy observer affirming that he has witnessed it, is conclusive. All luminous insects are capricious in displaying their radiance; and, in many instances, it is only under a certain combination of circumstances that they can do it at all. In the present case, it may be that only one of the sexes is luminous, and even in the sex so endowed, the property may depend on the age of the individual, the season of the year, and even the state of the atmosphere. The narrow-snouted Fulgoræ have likewise obtained credit for being luminous, but there is a still