114 ON TWO NEW SPECIES OF HELIX, 



(America), and it is therefore perhaps more likely that it naturally 

 feeds on some other species of Solanum in the inland regions of 

 Africa, and has spread thence on a congenial food- plant being 

 brought to meet it. It remains only to suggest an effectual remedy ; 

 this I am, unfortunately, unable to do. The larva being an 

 internal feeder, no external washes or dressings could produce 

 any effect, nor is it discoverable without digging up the plant. 

 Should a crop be discovered, on harvesting, to be infested with 

 this insect, the worthless tubers should not be thrown aside, but 

 carefully destroyed with fire ; this would go far to diminish the 

 numbers of the insects next season, but although it might keep 

 them in check, would not be effectual as a cure ; and the moth, 

 whose appearance would soon be learnt, might also be destroyed 

 when seen. As the insect is now established, no other precautions 

 are available. 



On two new species of Helix from the Lotjisiade Archipelago, 



By James C. Cox, M.D., F.L.S., &c, 



Plate 16. 



1. — Helix (Geotrochus) gurgtjstii, Fig. 1. 



Shell imperf orate, broadly conoid, white, diaphanous, opaque, 

 shining, granular on the surface ; whorls fine, gradually increasing 

 in size, flat, last sharply angled at the periphery, pinched and 

 everted at the peristome, reflexed at the insertion ; base flat ; 

 peristome bright pink, lunulately-elongated, margins approached, 

 everted and beaked at the centre ; aperture white within. 



Diameter, greatest 1*10; least 0*84; height 0-80 of an inch. 



Habitat, Eossell Island, Louisiade Islands, Torres' Straits. 



This fine species is in the Hargravesian Collection in the 

 Australian Museum; it is the same type of shell as Helix 

 Louisiademis of MacGrillivray, but is a larger species, easily 



