146 Note on Certain Insect Larva-Sacs. 



Try on {Amer. Journ. of Conchology, Part I., February, 1865) 

 justly remarks : — "This fresh description of Phryganice as Val- 

 vatce is amusing; naturalists seem resolved to consider them 

 Mollusca !" 



As these Helicopsyche-sacs have from time to time attracted 

 much attention, and their true character has been misappre- 

 hended, I add a copy of an interesting note on the subject 

 from Von Siebold's work On a true Parthenogenesis in Moths 

 and Bees (English translation by "W. S. Dallas, pp. 28-30. 

 London, 1857). 



" Besides Psyche Helix, there are some other insects whose larvse, as 

 case-bearers, manufacture sacs in the form of a snail-shell. In the genus 

 Psyche itself there occurs another species, the caterpillars of which, 

 like those of Psyche Helix, bear about with them a spirally-twisted 

 sac. By the kindness of Heir Zeller of Glogau, and Dr. Rosenhauer 

 of Erlangen, I possess two earth-colored, snail-like sacs, with perfectly 

 fl»t convolutions (Figs. 15-1 7), found in Sicily and Spain. They are 

 nearly three times as large as the sacs of Psyche Helix, and from their 

 different form and size belong to another species, to which I will give 

 the provisional name of Psyche Planorbis. Both sacs, like those of 

 Psyche Helix, are covered with fine grains of earth and sand cemented 

 on them. Behind the uppermost and narrowest half-turn there is also 

 a lateral aperture, which is due to an interruption in the walls of the 

 sac taking place here (Fig. 15, a). 



" In the family of the Phryganidce, also, larvse occur, which form a 

 spirally-twisted domicile. . The first notice of this was furnished by 

 Shuttleworth (in the Mittheilungen der naturforschenden Gesellschaft in 

 Bern, June, 1843, p. 20), and as this is but little known, I will repro- 

 duce it here literally. The passage in question runs as follows : 

 1 Amongst the mollusca collected by Blauner in Corsica, there was a 

 considerable number of a shell, which was at first taken for an unde- 

 scribed species of Valvata, and which appeared to be nearly allied, if 

 not identical, with the Valvata arenifera of Lea (Observ. p. 114, tab. 15, 

 Figs. 36, a and b), from North America. The perfectly regular, spirally 

 convoluted shell consists of a very fine transparent membrane, upon 

 which very small grains of sand and stones are fixed with the greatest 

 regularity. The circular orifice is closed by a very delicate, apparently 



