IN HIGHER INVERTEBRATES 55 
might profitably attempt. The habits of Insects and other higher 
Invertebrates offer an inexhaustible and intensely-interesting field 
to multitudes of such workers. Accurate observations recorded 
with scrupulous exactness are here badly needed, and those who 
enlarge our knowledge in this direction are contributing to the 
advance of two branches of knowledge, zoology and the science 
of mind (psychology), not to mention sociology and education, 
both of which are intimately connected with the latter. 
It is indispensable that observations on instinct and intelligence, 
should be made with a perfectly open mind, and not with the 
object of collecting material for the support of this or that view. 
And it is peculiarly necessary to remember that the mental 
standard of human beings can only be applied with many reser- 
vations in explanation of the actions of animals, especially when 
dealing with creatures like Insects which, though of highly com- 
plex structure, have specialized on lines of their own. A series 
of observations made in this spirit, and which are not only of the 
utmost value but of absorbing interest, have been recorded by Dr. 
and Mrs. Peckham (Ox the Habits and Instincts of the Solitary 
Wasps). These insects have attracted much attention on account 
of their habit of storing up caterpillars, flies, spiders, &c., for the 
benefit of their progeny, the victims having previously been stung 
(see vol. iii, p. 391). Instincts of very complex nature are here 
involved, but the zoologists just mentioned have shown that these 
instincts are not so stereotyped as commonly supposed, there being 
a certain amount of adaptability to circumstances, which is strong 
presumptive proof of some degree of intelligence. Pure instinct 
is manifested by the fact that any particular species of these wasps 
is always found to select the same kind of prey, and, for a given 
species, there is so much uniformity in the mode of nest-construc- 
tion, the way of disabling the victims, the manner of taking them 
into the nest, &c., that instinct is undoubtedly the dominant factor. 
But, except in regard to the kind of prey, there is a sufficient 
amount of adjustment to varying circumstances to warrant the 
conclusion that intelligence also plays some part in the complex 
series of operations. It appears, for example, that the prey is not 
uniformly stung in the nerve-cord, as once believed, and it may be 
killed instead of paralysed by its injuries, proving in either case 
suitable food for the larve. This certainly discounts the view 
that this part of the series of actions is stereotyped by instinct. 
