C. W. Johnson.
Diptera Destroying Snails.
Psyche 36(2):106, 1929.

This article at Hindawi Publishing: https://doi.org/10.1155/1929/21785
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106 Psyche [June
the C. cassius described from the Congo. If the hypothesis which I advanced in my paper of 1928 be accepted, the latter specimen may be supposed to have been infected by Mermis as an adult worker minor larva just before spinning its co- coon, whereas the minutior mermithergate was infected as a queen larva which had developed slightly beyond the stage at which, by some difference in feeding, it might have been converted into a normal worker major.
DIPTERA DESTROYING SNAILS
In a series of papers entitled "Natural History Notes from North Carolina" (Journ. Cincinnati Soc. Nat. Hist., vol. 17, p. 72, 1894), A. G. Wetherby under Zonites elliotti Redf. says: "This shell is destroyed by a parasitic larva, the imago of which is a small and active species of Diptera. The grown larva occupies the shell as a pupa house after devour- ing the inmate. I have noticed this habit of the Diptera in the case of but one other species, and that is Polygyra fas- tigans Say. At the only locality where I have collected this latter species, more than half the snails were affected, and the number of dead shells holding the empty pupa cases, were sufficient testimony to the activity of the parasite." It would be interesting to know what this fly really is. A small Sarcophagid-Helicobia helicis Town. was bred from a snail-Polygyra thyroidus Say. I have always looked up this record as only accidental, for the fly is common and has been bred from a number of species of insects, and in many cases is considered a true parasite (Aldrich, "Sarco- phaga and Allies in North America, pp. 158-161, 1916). Dr. J. Bequaert however, has described a Sarcophagid repre- senting a new genus and species-Mdacophagula neotropica from a snail-Bulimulus tenuissimus at Para, Brazil, which he considers a true parasite of the snail (Journ. Parasito- logy, VO~. XI, pp. 201-212, 1925).
C. W. JOHNSON.
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