334 THE FRESH-WATER LOCHS OF SCOTLAND 
Fresh- water Plankton of Scottish Lochs.'*' ^ Messrs West distinguish 
12 species. 
72L Peridinkim tahulatum^ Ehr. Common. 
722. CeraUum Mrimdinella^ Miill. Very common. 
723. C. cornuium (Ehr.). Frequent. 
724. Glenodinium cinctum, Ehr. Loch Ness. 
INSECTS. 
Mr Grimshaw has examined a small collection of insects, and 
given us some notes upon them. Most of them were in nnmature 
stages, and the species could not be identified, but Mr Grimshaw has 
indicated the families, and, where possible, the genera. The insects in 
the following list were all collected in Loch Ness. 
Gerris ? costce^ H. Schff. (nymph). 
Corixa prceiista, Fieb. 
C.fahricii, Fieb. 
C. f distinda, Fieb. 
Ephemeridae, nymphs of two species ; nymph of a large species 
probably belonging to the genus Baetis. 
Trichoptera^ larvae. Cases and larvae of Oxyethira or other 
Hydroptilid. 
Perlidae, larvae. 
Culex sp., pupa. 
Chironomidae, larvae. 
PJatamhus macidatus^ L. 
H all plus fulvus^ L. 
Hijdroporus septentrionalis^ Gryll. 
Laccoh'ms miimdus^ L. 
1 Trans. Roy. Soc. Edi?i., vol. xli. p. 493, 1905. 
