48 



several black dots on the thorax and wing covers, and om 

 the latter at each side is a margininal line of dull red 

 from which are given off three branches which project 

 obliquely backward. The latter markings give the spe- 

 cies its technical name tridentata. 



Quite a number of parasites, small four- 

 winged flies, were obtained from wood 

 from a diseased Frankfort elm, but since 

 there were three other borers besides the 

 one described above, at work on the wood 



Fig. 13. The it is not certain which species they were 

 adult of the . _, ,■• ir 



elm borer. preying upon. The presumption is irom 



the greater numbers in which the elm borer occurred that 



they come from it, and there is reason to hope that 



these friends of ours will greatly increase. 



The adult beetles emerged at the Station during May 



and the first half of June. A single living example was 



taken from the boxes which our infested wood was kept on 



July 21, hence the beetles are probably abroad during 



some portion of July also. 



REMEDIAL TREATMENT. 



It will be seen from the statements already made that 

 the borers are in the bark of trees during the fall and 

 winter months, and it is plain that if affected trees could 

 be cut down and burned at this time large numbers of 

 the insects would be destroyed. This practice is to be 

 be recommended for all trees which are plainly past 

 saving. Burning during the spring and early summer 

 could not serve a useful purpose because the beetles are 

 out of the bark during this part of the year. 



To defend trees from attack it may be suggested that 

 the trunks and if possible the larger branches be coated 

 with whitewash to which Paris green has been added in 

 the proportion of i pound to ten gallons of the wash. 

 This poison is known to have a good effect in saving 



