402 Transactions of the Society. 



are yet a matter of conjecture ; indeed, the amount of care and 

 patience required for the working out of these are sufficient to 

 deter all but the most enthusiastic. I do not think that the work 

 of the field naturalist, the accurate and minute noting of habit 

 and life-history, can be overvalued, but I would point out another 

 method, which, while it cannot supersede, can absolutely confirm 

 as well as suggest further observation, and by its unaided use 

 show a great number of structures, that on account of their minute- 

 ness are visible by no other means. This method I have applied 

 mainly to the insect in the imaginal stage, which, owing to the 

 quickness of movement in life, is the most difficult of observation, 

 but it can be used with advantage in the study of the more simple 

 larva. It has often been my experience to hear speakers depre- 

 ciate the method of those who mount whole insects with pressure, 

 the softer parts being dissolved and the object cleared in caustic 

 potash. Their objections are good from many points of view, but 

 the fact remains, that this method is the only one that will enable 

 the student to use the higher powers of the Microscope ; and it is 

 just this use of the high powers that is absolutely necessary for a 

 complete study of a preparation, which when well mounted, ex- 

 hibits all points of structure, and of difference other than colour, 

 that the examination of a pinned specimen can show, and multi- 

 tudes of detail that are beyond the powers of resolution of the 

 simple lens. It is true that allowances have to be made for altered 

 shapes and relations, but experience and study will give an idea of 

 the changes undergone, and enable the student to reconstruct the 

 original form of his subject in a mental image. 



I shall endeavour to show that it is possible to take a prepara- 

 tion of an insect that may be quite unfamiliar, and sitting by a 

 comfortable fireside, with a Microscope conveniently arranged, 

 study it: (1) place it in its particular order, family and genus; 

 (2) ascertain its sex ; (3) describe its habits, whether blood-sucking, 

 predaceous, or otherwise ; (4) show how it obtains its food or attacks 

 its prey ; (5) tell what that food is, sometimes naming the animal, 

 plant, or insect, that serves as such ; (6) know if it crawls on the 

 earth, flies in the air, swims in or skates on the water, or is para- 

 sitic ; (7) see how the insect smells, tastes, hears and feels ; (8) trace 

 the differences that shade from species to species ; (9) see the 

 remains of the organs of the past, examining their minute remnants : 

 (10) see that there is nothing in Nature that is not logical and has 

 not a "why and a wherefore"; (11) and be convinced that all 

 these observations strengthen and fit in with that great fact of 

 Evolution, which has so altered, for the man who thinks, the aspect 

 of the earth as well as that of the heavens. But the field of 

 inquiry is so large and the mass of detail so bewildering, that the 

 student of " life-history " must use method in his investigations, 

 and it appears to me that he will best obtain data bearing on his 



