COLEOPTERA ON SJJOWDON*. 343 



two months earlier. A very puzzling little Loni/itarsK^ was plentiful 

 all over the mountain, and has been referred by different people to 

 ballotae or rcic/wi. Water-collecting produced a few specimens each of 

 Hi/(lro])()rns riralis, H. darisi, H. ni'i/rita and 77. melcniarins. A;iahus 

 hipustttlatna var. solieri (?) was, of course, common. This variety was 

 described by Newman as var. mowilnniiis [Ent. Mwj., i., 55). Miscel- 

 laneous collecting produced Anthrrophai/Ks pallcns, Scirtes hemi- 

 sphaericKs, and the variety hicolor of Tachinus si(btc'rranrui<. 



The moss towards the top of the mountain proved most productive, 

 and yielded surprises of the first water amongst the Brachelytra. 

 First and foremost comes Ocj/iisa hibcrnica, of which Mr. Champion 

 took a single specimen (the type) on the top of Slieve Donard, Co. 

 Down, twenty-five years ago. Dr. Sharp took another specimen at 

 Braemar. Rye's name is, therefore, somewhat of a misnomer. We also 

 took (Kvi/jioda n(j)icula, sparingly — a mountain species which also 

 occurred with Oci/usa hibcrnica in Ireland. Ocyusa incrassata, 

 Hoiiialuta tibialis, H. ercmita, occurred more or less scantily, and 

 single specimens of Tackinna clo)i;/atiis, Humalota subi/labra (?), PJii- 

 lonthiis nif/rita, Antheyophafjiis alpinKft, and Gcoclromicus (/lubalicollis. By 

 dint of hard work we both secured nice series of Acichta crcnata. Our 

 experience tends to show that the moss is more productive in wet than 

 in dry weather, in spite of the discomfort of shaking and examining it 

 under a heavy rain. 



It was a fortunate chance that impelled us on August 19th, when 

 descending via Clogwyn, to turn aside for a look at the small 

 mountain tarn known to the initiated as Llyn du'r Arddu, whose blue- 

 black waters are a conspicuous object at the foot of the precipice of 

 Clogwyn du'r Arddu, about 2000 feet up on the Llanberis side. We 

 were astonished to find along the north-eastern margins of the tarn a 

 seething mass of struggling insects, mostly beetles, though nearly all 

 orders were represented. This mass was being constantly augmented 

 by a steady stream of insects setting in across the surface of the water 

 under the influence of the prevailing south-west wind, which had 

 varied but a few points during the whole of the preceding week. 

 Many were drowned but myriads were very much alive to the situation 

 and crawled ashore to dry as soon as the drift gave them a chance. 

 Nor was even the minutest particle of drift-wood untenanted ; even 

 the larger beetles and plant-bugs had willy-nilly to carry a crew, 

 which was often piled up three or four stories high. After the first 

 excitement of decimating these mariners was over, one naturally began 

 to ask old Aeneas' question to the Sibyl — " Quid vult concursus ad 

 amnem?" The preceding week had been accompanied by constant 

 torrents of rain, and the reason first naturally presenting itself was 

 that they had been washed down by the swollen mountain torrents 

 and freshets. Many had undoubtedly been thus assembled, but further 

 inspection showed that a large number of insects were of lowland 

 origin, species attached to fir, oak, heather and other vegetation, such 

 as only grows hundreds of feet lower down, in the valleys beneath. 

 We have, therefore, no hesitation in adducing wind as an even more 

 important factor than water in causing this phenomenon. The period 

 of hot weather which had succeeded a spell of cold and rain only a 

 day or two before our first visit would, as usual, produce a steady and 

 somewhat strong diurnal current of air towards the sooner heated 



