ABUNDANCE OR OTHERWISE OF LEPIDOPTERA. 245 



Istly. Diurnal Lepidoptera, and such of the Heteroceia as 

 spin liglit cocoons or hybernate as larvae above ground would, 

 during a mild damp. winter such as the last, fall an easy prey to 

 slugs, beetles, woodlice, Sec, whose rambles are stopped or 

 checked by frost, snow, and low temperatures ; whilst subterranean 

 larvae and pupse would be unafiected thus. Hybernating ichneu- 

 mons also might be expected to survive in proportionately larger 

 numbers, but this would only affect the crop of Lepidoptera this 

 autumn or next spring. 



2ndly. The prevalence of extremely high winds last year and 

 the early part of 1882 might be expected to destroy arboreal 

 larvse, whilst those of the marshes, or such as feed on low-growing 

 herbage, would be little or not at all injured. 



3rd. Heavy summer rainfalls would, as well as violent hail, 

 act in precisely a similar manner, but I cannot help thinking that 

 the cause that has operated most disastrous!}^ in the present 

 season, at least on a portion of our entomological fauna, is the 

 warm and sunny weather which forced on the vegetation early in 

 spring, which was succeeded by a bitter and withering frost, keen 

 enough, as I noticed, to blight the young leaves and sprouts 

 of ivy, and which I believe prevailed very generally over the 

 United Kingdom. 



I need scarcely advert to the influence exercised by the 

 weather upon the success of the entomological captures, an 

 influence which is often inexplicable, that of wind, however, being 

 excluded. 



At the Isle of Man I learnt that scarcely any Dianthcecia casia 

 or D. capsojjliila have been taken at Douglas Lighthouse this 

 year, owing to the prevalence of high winds ; but the capsules of 

 the Silene in that neighbourhood bore witness to the ravages of 

 an abundant su})ply of Diaiithmcia larvee. 



In May and June I myself experienced the potency of atmo- 

 spheric influences on the flight of nocturnal Lepidoptera, taking 

 scarcely any during the last Aveek of May, until, a change occur- 

 ring, I filled my setting-house in a few nights with an abundant 

 supply, whose numbers, both individually and in variety of species, 

 surpassed my previous experience. Throughout June there was 

 no lack of insects in such parts of Ireland as I have worked, but 

 July and August have proved exceedingly barren, especially 

 as to forest insects ; though I can scarcely complain of such 



