4 WASP STUDIES AFIELD 



of the complete cycle of behavior of any single species can- 

 not be thus obtained. Field study is therefore indispensable 

 and this demands acute powers of observation, much pa- 

 tience and no little mere physical endurance. Still the 

 limitations of such study are obvious. The finding of the 

 insects and their nests is a matter of chance and frequently 

 only glimpses of their behavior are obtainable so that the 

 whole cycle of behavior has to be pieced together from 

 fragmentary observations and often requires the labor of 

 several observers extending over many seasons. Hence the 

 incompleteness of many accounts in the literature. A good 

 example of this limitation is seen in the present volume in 

 the interesting account of the extraordinary parasitic habits 

 of Stizus unicinctus. 



Another limitation in field study lies in one's inability 

 to estimate the previous experience of the wasps under ob- 

 servation. Usually the insects are first encountered while 

 engaged in some activity which may or may not have been 

 repeated on some former occasion, such as making the nest 

 or provisioning it, and as they undoubtedly profit by ex- 

 perience and form definite habits, what is evidently an 

 important factor in the performance of the particular activ- 

 ity under observation cannot be taken into consideration. 

 This lacuna is partially bridged in Chapter XII of the pres- 

 ent book by a valuable study of individual experience in one 

 of the primitive wasps, Polistes. 



Even more serious is the limitation to the experimental 

 method in the field. It is, of course, essential for descrip- 

 tive and other purposes to ascertain by simple observation 

 the course of the normal routine activities of the insect in 

 its natural environment, but it is also of great importance 

 to know what the insect is and is not capable of doing. This 

 can be accomplished only by means of experiment; and 

 experimentation in the field is a rather mild procedure 



