FISHERIES, GAME AND FORESTS. 37 1 



Cctlosoma scrutator Fabr., is another enemy. This beneficial species is comparatively- 

 rare however. Two predaceous bugs, Podisus placidus Uhler and P. serieventris 

 Uhler, prey on the caterpillars, as recorded by Mr Kirkland. The yellow and black 

 billed cuckoos feed upon the spiny caterpillars. 



Remedies. The gregarious habit of the caterpillars may be taken advantage of to 

 cut off the branch on which they are clustered and then they may be killed by crush- 

 ing. They may be dislodged by shaking, jarring with a padded mallet or by use 

 of a torch and then crushed upon the ground. This species can also be controlled 

 by spraying with an arsenical poison and when the caterpillars are very abundant, 

 this will probably prove the most satisfactory way of controlling the insect. 



Elm P) or e r - 



Saperda tridentata Olivier. 



This beetle is sometimes as injurious to the beautiful white elm as the sugar 

 maple borer, Plagionotus speciosus Say, is to the sugar maple, and in places where 

 this elm pest has become well established, even greater injury may result from its 

 attacks. This is probably due to the greater prolificacy of the elm pest which some- 

 times occurs in large numbers beneath the bark, while the maple borer is usually 

 present in much smaller numbers. The infested elms are also attacked by other 

 insects, as will be shown in a subsequent paragraph, and the ultimate result is very 

 disastrous to the trees. 



Characteristics of attack. It is difficult to detect this insect till it has become 

 well established and the first signs are usually seen in the lighter, thinner foliage 

 followed by a limb dying here and there. Soon indications of boring are appa- 

 rent in the dark sawdust collected in crevices of the bark and after the attack 

 has progressed for some time, large portions of the bark can be easily pulled from 

 the tree, revealing a condition beneath very much like that represented at figure 3 on 

 plate 3. The inner part of the bark may be literally a mass of mines or burrows 

 and if the work has not gone too far, numerous whitish, flattened, legless grubs may 

 be found in the channels they have eaten out. The photograph reproduced here- 

 with, figure 7, shows very well the condition of the trees after this pest has worked 

 on them for a number of years. It was taken May 30, 1900, at Berlin, Mass., by Mr 

 J. A. Otterson, and represents a small portion of two long rows of comparatively 

 young trees. 



