28 THE entomologist's record. 



of the authorities on these subjects up to the date of publication 

 (1898), and much additional information on them will be found in Dr. 

 Sharp's U\o volumes on Insects, in the Canibridi/e Xatiiral History. 

 The veteran J. H. Fabre continues the fascinating story of his own 

 observations and experiments on the habits and instincts of insects, 

 and his example has l)een effectively followed by Mr. and Mrs. Peckham 

 in North America. Lord Avebury's experiments on the social species 

 are too well known and appreciated to need more than a passing 

 reference. 



Nature, " so careful of the type," may in a sense be said, like the 

 British nation in difficulties, to "blunder through somehow," and 

 with a similar carnage of individual lives, but with complete success 

 in the preservation and development of species in infinite variety. 

 It is the "somehow" that we want to know. She moves in 

 a crowd, in surroundings so numerous and changeful that in 

 order to be sure that Ave ascribe results to their proper causes 

 it is often necessary to resort to experiment, by which elements that 

 might disturb are excluded. In relation to the functions of organs of 

 living animals, which add their OAvn active personality to the other 

 factors, the complication is often increased. In this kind of investiga- 

 tion much valuable work has been done. The more recent volumes of 

 the Transactions of the Entomological Societi/ of Loiidon bear testimony 

 to the growth of experimental work in entomology. Quite a large 

 class of experiments showing the direct effect of their surroundings on 

 the aspect of larv;e and of pupje, has been conducted with great 

 patience and skill by Professor Poulton, Avhose observations make a 

 substantial advance in the solution of some of the mysteries of the 

 variability of their colours, and he has been seconded by other 

 observers. The results obtained by him are strongly indicative of the 

 protection afforded by those colours which are provided by natural 

 surroundings, but he bears testimony to his sense of the value of 

 experimental confirmation on all points by the careful observations he 

 has recently been making on the actual extent to which pupa9 under 

 various circumstances have been found to be in fact protected by the 

 special colouring from being carried off" by birds and other enemies. 



A striking illustration of the loose methods once in vogue for 

 dealing with natural phenomena, as compared with the modern 

 scientific one, is seen in the treatment of the question of the mode in 

 which a soft and fluffy moth (Dicranara rinula) penetrates its horny 

 cocoon. I remember about half a century ago being presented with 

 a book on insects, published under the auspices of a very pretentious 

 society of the time. Its author was lost in admiration of the 

 process of softening, which he said was performed by means of an acid 

 so potent that it ought to be contained in a vessel of glass, whereas 

 this insect had only a membranous bag. In 1892 Mr. Oswald Latter, 

 of Charterhouse, instead of taking things for granted, looked into them 

 himself, and demonstrated that the fluid was not an acid at all, but an 

 alkali, potassium hydroxide, and that the insect was also furnished 

 with a pair of sharply pointed organs for piercing the softened material, 

 and a shield for protecting its downy head and thorax from injury in 

 the process of pushing through. 



A large series of experiments has established that temperature in 

 the pupal period is one cause of the variation in colour of lepidoptera. 



