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NEW YORK STATE MUSEUM 



nized by its cylindric dark brown abdomen with yellow mark- 

 ings as represented in fig. 1. 



The female deposits her eggs in the trunks of sickly trees, 

 where the larvae run large cylindric burrows. Many elms in 

 both Albany and Troy show numerous holes caused in this way. 

 This borer has a deadly parasite in the lunate long sting, 

 Thalessa lunator Fabr. This beneficial insect is of 

 great aid in keeping the Tremex under control. The remains 

 of 13 ovipositors were found by the writer in the trunk of one 

 small elm. In their efforts to reach the numerous borers in the 

 tree, the females had driven their long ovipositors so far into 

 the wood that they were unable to withdraw them. 



Another insect which infests debilitated elms is known as the 

 elm borer, Saperda tridentata Olivier. The larvae of 

 this beetle run their burrows under the bark and in the sapwood 

 of the trunk, not many penetrating to a greater depth than an 

 inch. Their burrows frequently become so numerous as to 

 girdle trees two or three feet in diameter. An infested elm may 

 be recognized by the patches of unhealthy bark; in case of a 

 bad infestation large pieces become loose and scale off easily. 

 The beetle is usually less than J inch long, and of a dull slate 

 color, with the thorax and wing-covers margined with dull 

 orange (fig. 2). 



Fig. 2 Saperda tridentata (twice natural size^ 

 NATURAL ENEMIES OF EL.M LEAF BEETLE 



The natural checks serving so well to keep thousands of 

 insects under control which otherwise would be very destructive, 

 are unable to reduce the numbers of this beetle to a relatively 

 harmless figure. One of the more important natural agents is 



