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Syrphus Flies — Part 2

Those syrphus flies which live, in their early stages, in the nests of bumblebees belong to the genus Volucella, and the flies of this genus rather closely resemble bumblebees. Their larvae were for a long time considered to be parasitic upon the young of the bumblebees but later observations have practically disproved this and we are forced to conclude that the Volucella larvae are simply scavengers, feeding upon the waste or excreta of the bee larvae and even upon the dead bodies of those which die. The bumblebees seem to realize that the syrphus flies are not inimical to them, since they allow them free access to their nests and do not seem in the least disturbed by their presence.

The most famous of all the syrphus flies is the one which commonly goes by the name of the drone fly. It is Eristalis tenax and its larva is one of the rat-tailed maggots. It is a cosmopolitan species and is rather larger than the honey-bee, which it closely resembles. It frequents flowers and is commonly found in houses on windows late in the autumn. The larvae are found in soft mud and in privies, where they feed upon decaying animal and vegetable matter, transforming to pupa within the last larval skin. Osten Sacken, in two interesting papers on the so-called "Bugonia myth," shows that this idea, which has been prevalent since ancient times and which is that the carcasses of animals may generate swarms of honey-bees, has probably arisen from the fact that this drone fly, breeding in carcasses, has almost universally been mistaken for the honey-bee. The learned Russian author shows the existence of this myth with many nations, including the Chinese and the Japanese. It is mentioned in many places in ancient literature and even occurs in the story of Sampson, in the book of Judges in the Old Testament.

This family is probably the most attractive group of flies. A collection of specimens is a most interesting one, both from the aesthetic and the scientific point of view. The very frequent instances of protective mimicry referred to above, in themselves should give a great impetus to the study of the group. Moreover, we in this country are most fortunate from the fact that most of our species have been carefully studied and an admirable monograph by Dr. Williston has been published by the National Museum, which is one of the most perfect works of its kind which the entomologist is able to consult. A careful work on the life histories of these insects, however, is almost as greatly needed as in the other families of flies. The statements which have been given above are general, but in searching for specific accounts of individual life histories we find that they are lacking.