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 (On 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 larvae. This certainly discounts the view 

 that this part of the series of actions is stereotyped by instinct. 



