180 MR. C. B. HARDENBURG 



on the stem mav be caused by an Arhclid : thorns on a 

 branch of a tree which is smooth barked mav be made 

 by a Geometrid in its resting position, or a bagworm. 

 In fact, the various abnormalities which one meets with 

 durinof a day in the field are too numerous to mention, 

 and each has its significance. 



But, notwithstanding a sharp eye and a quick appre- 

 hension of the cause of anything abnormal, there are 

 several species which would still escape our search; for 

 these species other methods will be found necessary. The 

 use of the sweeping net over grass and low herbage will 

 often yield a good harvest of caterpillars which otherwise 

 could be obtained only by a very laborious search ; a 

 search which in many cases might remain unsuccessful, 

 as the larvie might drop to the ground when disturbed 

 and could not be found again amongst the roots and 

 debris. 



For caterpillars on trees and shrubs we have obtained 

 excellent results from beating and shaking the branches 

 over an umbrella^ one which has a white inside lining 

 covering the ribs is most suitable for the purpose. The 

 branch must be beaten or shaken suddenly and vigorously 

 as a preliminary slUjht jar will, in the majority of cases, 

 cause the caterpillar to hold on more tightly. 



But there is still anotlier class of caterpillars which 

 mimic their surroundings so closely and keep themselves 

 so quiet as to deceive even an experienced collector. 

 This applies especially to such as live among the lichen 

 on trees, or hide in cracks and crevices on the trunk. As 

 long as they remain motionless it is in many cases almost 

 hopeless to look for them. In several instances of this 

 kind I found that blowing a puff of smoke over the place 

 suspected will cause a sudden movement on the part of 

 the caterpillars so that they can be located and picked 

 off, or, if too deeply witlidrawn to be readily extracted, 

 they can by continuous smoking be induced to leave their 

 hiding places. P>ut one must be careful. Some of these, 

 although perfectly quiet while left alone, will, upon being 



