NOTES ON LAND AND FRESH- WATER MOLLUSCA. 85 



into and the centre or pith eaten away by some insect, which proved to be 

 Hylurgus piniperda. In one or two instances the Pines had been planted 

 out where they were intended to remain to form ornamental trees on lawns; 

 the consequence was they had to be taken up as useless, for when once the 

 leader of a Pinus is destroyed, the beauty of the future tree is destroyed 

 also. From the quantity of elms which abound in this county, the larvae of 

 Scolytus destructor are very numerous; I have had a difficulty of obtaining 

 specimens of the perfect insect, but have at length succeeded in taking three 

 or four specimens. 



Of the family Leptura I have only been able to take one species, Leptiira 

 verbasci. The larva of this lives in dead wood, such as stakes used in gardens, 

 etc. In 18 j1 I saw the work of an insect in a laurel stake used for staking 

 raspberries; I with m}'^ knife cut away the bark and wood till I arrived at 

 the end of the hole, which was worked round the stake beneath the bark but 

 not touching it; the hole was filled up with the gnawings of the larvae, but 

 it did not appear to have passed through it in the shape of food. The insect 

 when found had passed through the larva state into the pupa, which was 

 nearly white, and not enclosed in any cocoon or horny chrysalis, but merely 

 enveloped in a transparent skin, so the perfect insect could be distinctly seen 

 through it; the insect was without any colouring, that is, black or yellow, 

 the larva itself I have not seen, so cannot give any description. The habits of 

 this species no doubt have been observed before by others, but I have not seen 

 it; I shall be glad should I have added anything in its habits or economy not 

 before observed, as anything in the habits and economy of insect life tends to 

 one's knowledge and gratification. The beautiful and curious little Tortoise Beetle, 

 (Cassida viridisj is frequently to be met with in meadows on Cnicus arvensis. 

 I have also taken one specimen of Coccinella variabilis; it is the only one I 

 have seen. Thus ends my very poor and meagre list of Coleoptera. 



4, Muir-field Place, Exeter, December lO/h., I8o3. 



NOTES OX LAND AND FRESH-WATER MOLLUSCA. 



BY J. W. WATSON, ESQ. 



Perhaps a few remarks on some of the Land and Fresh-water Shells, which 

 have come under my oWn observation, may not be out of place in ''The 

 Naturalist." 



There is one circumstance with which I have often been struck, and I have no 

 doubt others have been so too, namely, that of the great sensitiveness to mois- 

 ture, which many of the Land Molluscs exhibit, particularly those inhabiting 

 mountainous and rocky districts, such as the genera pupa and vertigo, which are 

 generally found most abundantly on Limestone formations. Another very 

 sensitive Mollusc is Helix Lapicida. Well do I remember taking a walk of 

 six miles, one sultry summer's day, to the top of one of the Hambleton Hills, 



