382 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION, 



only on those that are old and hastening to decay, but preferably upon 

 those that are young and presumably vigorous. He observed them 

 almost daily from the middle of June to the end of July on shade treees 

 in Ottawa, or on trees in the neighboring woods. " On a tree not 

 more than 2 or 3 inches in diameter I have seen as many as eight 

 ovipositing at the same time, and have frequently observed two or 

 three at once upon small shade trees. Tremex in its endeavors to 

 oviposit through the tough, thick bark of the old trees frequently fails 

 in withdrawing its ovipositor, and scores of such self-immolated mar- 

 tyrs to the propagation of their race may be seen in the autumn dead 

 and dry. This is a fate that rarely befalls Xiphidria ; indeed, I have 

 only met with one instance of a dead specimen thus anchored. Hence 

 this insect will in many instances deposit successfully a much larger 

 proportion of its eggs than can its larger relativ^e, and thus stands a 

 better chance of rapidly increasing the species. * * • in July last 

 I found in a neighboring wood a dead tree on which the bark had 

 become shriveled and loosened. On removing a large patch of the 

 bark, the surface of the wood was found to be thoroughly riddled with 

 the holes of X. albicornis, either empty or still containing dead insects. 

 These had evidently been prevented from leaving their burrows by the 

 death of the tree and consequent drying and hardening of the bark. 

 Many others had partly penetrated the bark and then perished from 

 the same cause. The holes were slightly larger than would be made 

 by an ordinary knitting needle, and penetrated the solid wood perpen- 

 dicularly to some depth." (Rep. Ent. Soc, Ontario for 1883, p. 40.) 



The saw-fiy. — With a general resemblance to Tremex columba, it is much smaller, 

 and is black, with white markings and yellow legs. Females one half to two- 

 thirds inch long ; anteunte white ; thorax with a triangular white patch inclosing a 

 black dot on the shoulder and two small spots on the back between the hinder pair 

 of wings. Abdomen jet-black, except four to six light spots or semi-bands on each 

 side. The male ^s generally smaller, the abdomen flattened and rounded at the tip. 



Remedy. — Mr. Harrington proposes the use of a preparation made 

 by diluting soft-soap with a saturated solution of washing soda, which 

 must not be made too thin. This should be liberally applied with a 

 brush, so as to fill all crevices in the bark and give it a good coating. 

 As the female of Xiphidria, like those of the apple borers, seems 

 always to deposit her eggs in the trunk below the branches, it would 

 be quite possible to protect in this manner shade trees in towns and 

 districts where the insect was observed, especially recently trans- 

 planted trees, which the insect seems to single out as offering special 

 advantages for her future offspring ; perhaps because she can perceive 

 in them a weaker vitality, even when they are apparently flourishing. 

 The coating would have to be applied in the early part of June and 

 again a month later, as the insects occur during the greater part of 

 June and July. 



