THE NAUTILUS. 71 



HELIX HORTENSIS: I am sending under separate cover a spec- 

 imen of Helix hortensis Miiller. It was found in a prehistoric 

 shell-heap on Mahone Bay, about 75 miles west of Halifax, 



N. S. W. J. WUETEMBERG. 



A SYNONYMICAL NOTE: The shell described and named by 

 Pilsbry and Bryan in THE NAUTILUS, XXXI, 3, 1918, p. 99, 

 pi. IX, as Drupa walkerae from Honolulu Harbor, is the same 

 species which was described by G. B. Sowerby in the Annals 

 and Magazine of Natural History, Ser. 8, Vol. XVI, p. 166, 

 pi. X, 1915, as Pentadactylus fusco-imbricatus. A recent letter 

 from Sowerby and Fulton suggested this after an examination 

 of a specimen sent to them. A careful comparison of the de- 

 scriptions and figures convince us of the same conclusion. All 

 the specimens known are from the Honolulu Harbor dredgings 

 from May to August, 1915. The teeth vary from 5 to 7 in the 

 specimens before us. We hope to make a study of the varia- 

 tions of this and other shells later. 



F. GRINNELL, JR., 



J. M. OSTERGAARD. 



INSECT LARVAE DESTROYING PHYSA. There is a small artificial 

 pond in Waveland Park which joined my former home grounds 

 in Des Moines, Iowa, that I had never considered of much im- 

 portance conchologically, owing to its small size and rather 

 recent construction. A visit to it one day in the summer of 

 1907, however, only added greater strength to Mr. Simpson's 

 motto, " Look everywhere." 



I found here a form of Physa Integra Haldeman quite plenty, 

 but nearly all dead. They were enveloped in what at first ap- 

 peared to me to be a growth of moss, but which Dr. C. M. 

 Child of the Department of Zoology, University of Chicago, 

 pronounces as insect cases, ' ' probably some dipterous insect, 

 but none of the men in the Department are able to identify 

 more exactly the insect that is responsible for them." As I 

 have heard nothing further, it is fair to presume that the insect 

 is new or little known. 



The deposition and multiplication of these microscopical in- 



