184 
SLUGS AND FROST. 
June, 1891. 
* Onopordum Acanthium. 18, 21, 46, Severn D. Tab. 17. In all 
the districts. 
* Carduus nutans. 106, Avon D. Tab. 17. In all the districts. 
* C. acanthoides, lanceolatus. Tab. 17. In all the districts. 
* C. eriophorus. 47, Severn D. ; 68, Malvern ; 99, 100, Avon; 133, 
Dudley. 
* C. arvensis, palustris. Tab. 17. In all the districts. 
* C. pratensis. 35, Castle Morton; 47, between Tibberton and 
Crowle; 47, 61, Longdon Marsh ; 96, formerly at Feckenham, 
“Purton;” 98, Alderminster ; 119, formerly at Moseley. Tab. 
17. In all the districts. 
C. Fosteri. 47, near Tibberton. Tab. 17. Severn. First record. 
* C. acaulis, vii. 100,104, Avon D. Tab. 17. Avon, Severn, Malvern. 
(To be continued.) 
SLUGS AND FROST. 
Mr. E. J. Lowe, F.R.S., has communicated to the first 
number of “ The Conchologist ” the following observations 
on this subject:— 
“ It has been noticed that excessively cold winters, instead 
of (as generally supposed) destroying slugs, have a contrary 
effect, and this is very noticeable at the present time. A 
less frost with mild intervals, inducing the slugs to leave 
their winter quarters, would be more destructive than a con¬ 
tinuous frost. 
“ When the late frost commenced, the slugs congregated 
under leaves (good resisters of cold), but as the severity 
increased they disappeared, descending deeper and deeper 
into worm holes, &c., where they would find a warmer tem¬ 
perature ; but, now the frost has ceased, they are again on 
the surface, apparently with no diminution in their numbers. 
“ The following records bearing on this subject will be 
instructive. In the frost of 1860-61, and again in that of 
1879-80, some experiments were made as regards the amount 
of frost sufficient to kill slugs. &c. These may be briefly 
stated. A bell-glass was placed on a slate, under which were 
Avion ater, Limax flav us, L. maximus , L. agrestis, and Amalia 
marginata. When the temperature fell to 14° the slugs were 
frozen and stiff, and not one recovered, so that 18° of frost 
is enough to destroy their lives. Helix aspersa, under another 
glass, survived; it, like other non-operculated slugs, had a 
covering of a light layer of mucus (impregnated with cal¬ 
careous salts), which had the power of resisting many degrees 
of frost, for as salt water requires a greater degree of cold to 
freeze it than fresh water, no doubt this layer of mucus was 
a sufficient protection. The common gnat ( Culex pipiens), 
