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The Large Poplar Longhorn 



gradually enlarging the hole. The result is that the whole of the centre 

 of the leaf may be completely eaten out, and only the marginal portion 

 left intact (Fig. 21). The holes so made are of various patterns; they may 

 be circular, oval, elongate, or irregular, but in every case the serration 

 caused by the large biting mandibles of the adults, is distinct. By way 

 of contrast Fig. 21 shows two different kinds of damage. In this figure 

 the leaf on the left shows the work of an adult of S. carcharias in its 

 centre, while on its edge, at the right side of the base of its stalk, is the 

 work of a Lepidopterous larva. 



Flight. Both sexes have ample powers of flight but the males being 

 lighter than the females fly with greater ease and much more frequently. 



Fig. 21. Leaves of Populus tremula Linn, (natural size), showing characteristic injury 

 by S. carcharias adult. 



Taken indoors, both sexes fly readily, but in the open the females are 

 very restful. 



In the open the male beetle can soar to a considerable height. On 

 several occasions I have noticed them as high as 30 ft. in the air. They 

 can also fly a considerable distance at one time. The beetle in flight recalls 

 a biplane. The outstretched elytra, held almost at right angles to the 

 body, represent the upper plane, while the membranous wings stretched 

 almost parallel to the elytra, correspond to the lower plane. A loud 

 humming sound accompanies the flight of the beetle. 



Stridulation. If live specimens of either sex of Saperda carcharias are 



