NOTES ON COLLECTING, ETC. 96 



that many people lose these larvae, but mine have always been very 

 healthy, and I have hardly found a corpse in the brood, though, of 

 course, one is nothing like out of the wood yet. Talking of tlie ups and 

 downs of insect life, I think we get them in their most extreme limits 

 in the Fens. Laelia coenosa vanishes at Wicken, apparently never to 

 return. Cidaria sagittata, the larva3 of which was nothing accounted 

 of when Mr. Bowles and I were there some years ago, is now, I under- 

 stand, almost extinct. Then there is Agrotis suhrosea, burnt out and 

 destroyed, Chri/.'iophanns dispar long gone, Tapiuostohi concolor not long 

 rediscovered, etc. Even the insects which occur every year, vary 

 enormously in their numbers. Some years (even nights) you may catch 

 dozens, other years only odd ones. I have been several times to Horning, 

 but I never found Lenrania hrevilinea common, though it is so in some 



years. Mr. E. A. Atmore (King's Lynn) writes on Jan, 22nd: — 



" I cannot now be sure as to whether the recorded captures of Argij- 

 resthia iUnminateUa are from Aberdeenshire or Morayshire. I certainly 

 thought the former when writing my last note. My Argyresthia, which 

 is either illaminateUa, or comes very near it, seems to be attached to 

 larch, although Scotch fir grows alongside the larch trees where I take 



the insect." Dr. Riding (Buckerell) writes on Jan. 2oth : — " As 



to ' favourable seasons ' and the reverse, I think Mr. Burrows gives the 

 clue as to one condition, when he writes ' the larva? (and pupaj) had 

 been advancing too much and were caught.' The more undisturbed 

 both are the better the chance of success, and so a prolonged cold winter, 

 when the former have nothing to tempt them to look about, and keep 

 in winter quarters, is generally followed by an abundance of insects the 

 following season. Is not an unusual amount of wet also injurious ? 

 Larvae cannot stand a soaking, and the torrents and floods find out 

 their favourite snug corners, even though we cannot, and would be most 

 felt where the " cover " is least, as in the fens (which would agree with 

 Mr. Robinson's statement, that there is a greater variability in numbers 

 there, than elsewhere). No doubt each insect is a law to itself, and 

 conditions suiting some are fatal to others, but as a rule, I think, winters 

 with continuous cold and frost, and no intervening warm weeks, and 

 with only a moderate amount of rain, are those most likely to be followed 



by a season favourable to entomologists." Mr. Tutt writes on 



January 30th : — " The drought of 1893 undoubtedly very injuriously 

 affected such larvae as fed uj) in the summer, and ought to have gone 

 undergroiuid to pupate. To find a suitable spot necessitated crawling 

 about a considerable length of time, and increased the chances 

 of injury, discovery, etc. Probably many never did find a suitable spot 

 for pupation. Hybernating larvaj must hybernate at a certain age 

 (different of course for different species) ; if they get beyond that age, 

 they must go on to maturity, or die. The heat of 1893 would tempt or 

 force hundreds of larvje to go beyond this stage, and the autumn weather 

 would kill them off. Double broods were common in 1893. The 

 larvaj from such would hardly have reached the stage for hybernating, 

 before winter was on them. Hence they would die. These appear to 

 me to be some of the reasons why 1894 was such a bad season 

 entomologically." 



An act of vandalism. — The difficulty with regard to the extreme 

 localization of certain species of lepidoptera is one on which everyone 

 may hold his own view, but who can say that we thoroughly under- 



