( cxlii ) 



5. That insects, being endowed with nervous matter con- 

 trolling or guiding their movements, the psychic element 

 should be taken into account in considering their habits 

 and activities. 



6. That insect activities not directly concerned with nutri- 

 tion or reproduction are an important part of the lives 

 of many of them. 



7. That external circumstances promoting or checking the 

 energetic exercise of these activities may affect numbers, 

 and account in many cases for abundance or sparseness. 



8. That observation and record of the abundance or scarcity 

 of a species or variety, either generally or in any locality, 

 and of any permanent change in these respects, and 

 inquiry into its causes, is very desirable. 



9. That evidence of the processes by which the balance of 

 organisms as it applies to herbivorous insects is maintained 

 is desirable. 



10. That polymorphism, discriminate or indiscriminate (i. e. 

 the forms not appropi'iated to special situations in refer- 

 ence to time, space, or other circumstances), may be of 

 selection value. 



11. That under certain circumstances scarcity may be of 

 selection value. 



12. That a large number of conspicuous features sufficient in 

 themselves for selection are not in fact selected, but 

 jDcrsist irrespectively of it. 



13. That habits may be of selection value. 



Importance of field observations. 

 This brings me to the practical end and object of my 

 address, which is to invite attention to the great aid which 

 may be given towards the solution of problems presented to 

 naturalists, by extensive and systematic observation in the 

 field and the laboratory on living creatures. Apart from all 

 the specific questions which have been considered, we can 

 hardly do wrong in devoting attention to the observation and 

 record of the special habits of living things. It is life that 

 gives its surpassing interest to this insect world that we study, 



