CONDITIONS INFLUENCING THE APPEARANCE OF MOTHS. 101 



on two occasions only. A single M. cyanea was seen and captured 

 near Sparkford on Aug. 27th, and a small number of S. vulgatuiiif 

 of which one was captured, were found flying on Sept. 2nd over 

 a piece of swampy ground near the coast, a mile or two from 

 Bridport. 



'21, Knight's Park, Kingston-on-Thames, Feb. 3rd, 1896. 



METEOEOLOGICAL and OTHER CONDITIONS INFLUENCING 



THE APPEARANCE OF MOTHS. 



By B. N. Menshootkin. 



I SHOULD like to bring forward some notes respecting the 

 question of the nightly appearance of moths, and how it is 

 influenced by meteorological conditions. These conditions can 

 be divided into — (a) common, which may be applied to a 

 greater number of species ; and (h) particular, applying to 

 some, or even only one, species. 



The best possible time for moths appearing is, according to 

 observations, a few hours preceding a heavy night thunderstorm. 

 The moths are then literally swarming, and come in hundreds 

 to the sugar. Even rain for a long time does not drive them 

 away ; neither do they seem to mind the lightning and thunder. 



Warm nights are almost always productive, especially in the 

 spring and early summer ; the same can be said if the evening 

 and night are warmer than the day. But towards the middle of 

 the summer warm nights often prove a failure. I attribute this 

 to the fact that moths, as it seems, do not like very dry 

 evenings ; and warm nights of the middle and the end of 

 summer are always dry. Neither do they appreciate very wet 

 (but not rainy) evenings ; for instance, on evenings with heavy 

 dew, or after a heavy rain, collecting had better be put aside, as 

 no moths appear, with the exception of some mentioned below. 

 But a rainy evening is generally very productive, especially if the 

 temperature is high enough (some 14° to 15° Celsius), and the 

 rain is not falling very fast. Such evenings are sometimes 

 more productive than warm weather. The worst possible 

 evenings I have observed in cases of heavy wet fog, the result of 

 abundant rain during the daytime. Thus it will be seen that 

 wet evenings are not always unproductive, and, provided it rains 

 only a little, and the air is not cold, some nice captures may be 

 effected. 



The influence of wind is marked enough, and can be formu- 

 lated thus : the harder it blows, the fewer are the captures. 

 However, up to a certain degree, the intluence of wind may be 

 obviated by putting the sugar on places protected from it. Clear 

 and cloudy nights are also almost always marked: on clear nights 



