89 
kept in large glass jars with no cover whatever, as they seem to require 
plenty of fresh air. 
All of these indoors and rearing-cage notes, however, concern things 
which will gradually he learned by experience, and after all, with the 
majority of insects, nothing can take the place of outdoor work. I 
have given with so much detail in the early part of this paper the 
methods used in the investigation of Phorodon humuli, mainly to em- 
phasize this point. More particularly the case with Aphididse and 
Cynipidae, since these forms exhibit an alternation of food plant or an 
alternation of generation, the rule holds in only slightly lesser degree 
with all forms of insect life. To gain the clearest and most accurate 
idea of a life history the insect must be studied under perfectly natural 
conditions, and not under conditions which more or less imperfectly 
simulate the natural ones. There is no easy road to the most perfect 
knowledge of habits. It involves tramping through mud and bramble 
patches 5 it involves the constant risk of sunstroke, and in our South- 
ern country the constant presence of Leptus and Ixodes ; it involves 
constant watching and watching and watching, astride the small limb 
of a fruit tree, perhaps, on your back under bushes, on your knees in 
the wheat field, on your stomach in the pasture, with your face down 
close to a cow's dropping, and with the summer sun beating down upon 
your unprotected head, watching and watching until your eyes grow 
dim ; but in this way only are the unsolved problems in the life histories 
of injurious insects most satisfactorily worked out. 
Mr. Forbes wished to know how close Mr. Howard found it possible 
to keep the temperature of the insectary to the out-of-door temperature, 
and suggested the electric blower as a means of ventilation. Mr. How- 
ard thought that by proper contrivances for admitting air the tem- 
perature might be kept practically the same as that outside. 
Mr. Forbes thought that work on the life histories of insects carried 
on indoors should be verified constantly by observations on the same 
insects in their natural haunts. 
Mr. Garman suggested that some insects were much more influenced 
by being kept indoors than others, and stated that he has sometimes 
been surprised to find that insects kept in a dry and heated room went 
through their stages at the same times as those out-of-doors. 
The following paper was then read : 
