Economic entomology for the farmer Economic entomology for the farmer and fruit-grower economicentomolo01smit Year: 1906 35° AN ECONOMIC ENTOMOLOGY. quently found in privies or cesspools, sometimes appearing so suddenly and in such numbers that a suspicion is engendered that the specimens have been passed by the individuals using the out'house. In fact, I have on more than one occasion received the larvae with the positive statement that this had actually occurred. They are curious creatures, maggot-like in general shape, with a long, extensile, tail-like appendage at the anal ex- tremity. It
Economic entomology for the farmer Economic entomology for the farmer and fruit-grower economicentomolo01smit Year: 1906 35° AN ECONOMIC ENTOMOLOGY. quently found in privies or cesspools, sometimes appearing so suddenly and in such numbers that a suspicion is engendered that the specimens have been passed by the individuals using the out'house. In fact, I have on more than one occasion received the larvae with the positive statement that this had actually occurred. They are curious creatures, maggot-like in general shape, with a long, extensile, tail-like appendage at the anal ex- tremity. It is hollow or tube-like, and at the end is a spiracle, the use of this telescopic tail being simply to keep the opening above the surface of the filthy mass in which the insect lives, and thus to secure a supply of pure air. The larvae are called from this peculiarity '' rat- tailed.' The reason why the flies are sometimes so abundant in greenhouses is that somewhere in their vicinity, among semi-liquid manure, the best breeding- places can usually be found. Taken as a whole, this family SyrphidcB contains no really noxious insects, and many that are decidedly beneficial. It should be noted, however, that the larvae of some species feed upon pollen, and that others live in growing vegetable tissue ; hence it is not impossible that in the future this general statement may have to Fig. 402. Fig. 401 Rat-tailed larva oi Eristalis. Mesograpta po/i/a.—, pupa, and adult; all enlarged. be modified. One of the most common Eastern species, Meso- grapta poliia, has been found feeding in great numbers in the larval stage upon corn pollen, but without causing any real injury. Passing over several small families interesting enough in them- selves, but not of importance to the agriculturist, we reach the
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