178 MR. C. B. PIARDEXBURG 



is sent in for determination and for advice as to the best 

 remedial measures. In order to enable the entomologist 

 to deal with the matter promptly, he must be able to re- 

 cognise the insect in this stage ; aS;, if he must wait until 

 the species has been reared to the adult stage to deter- 

 mine it, the damage has been done and the advice comes 

 too late. To make a ready identification possible, a re- 

 ference collection of the caterpillars of these injurious 

 insects must be available, or such descriptions as will 

 enable one to determine the species in question with cer- 

 tainty. Otherwise it may happen that some injurious 

 larva is confused with a harmless one or vice versa; the 

 more so as there is sometimes a ver\' close superficial re- 

 semblance between caterpillars of these two groups. 



(c) The Scientific Value of the Study of Caterpillars: 

 — During the last decades the immature stages of the 

 Lepidoptera have been the subject of careful examination 

 and study on the part of the leading specialists, both in 

 Europe and elsewhere. While the present classification 

 is based on the characters of the imago, a study of the 

 larva often discloses the relationships of the various 

 families, etc., better than the adults. This is not the 

 place to go into details, and the matter has been dis- 

 cussed more fully elsewhere. However, I desire to point 

 out that for the purpose of tracing relationships, cater- 

 pillars in their first instar are the most important, and 

 one should therefore never lose an opportunity to collect 

 the eggs and save the newly hatched larvae. 



The Collecting of Caterpillars. 



While it would be an exaggeration to state that cater- 

 pillars occur everywhere, we may safely say that they 

 can be found almost everywhere. T>y this I mean that 

 they can be met with in the most unlikely situations. 

 Although, during the feeding period, the majority will 

 be found on or near their food-plant, tliere are several 

 species and groups of species which, when full grown, 

 travel for a considerable distance to find a suitable place 



