100 THE EEPOET OF THE No. 36 



Black Leaf 40, at one part to 100 gallons of water, with five pounds of soaji, 

 killed all the larva in the foliage sprayed. This is the application recommended. 

 It should be applied in late May or early June, as soon as the small brown mines 

 appear on the leaves and should be repeated as often as new mines appear from 

 reinfestation by late appearing adults or the migration of adult females from 

 neighboring breeding grounds. 



Immune Species of Alders. The various species and varieties of alders grow- 

 ing in the Arboretum are effected to very different degrees by the leaf-miner. Some 

 are very badly affected Avith other varieties beside them showing no signs of the 

 injury whatever; and there is evidence that individual trees of a variety possess 

 varying degrees of immunity. 



The Locust Boeer, Cyllene robinice Forst. 



The Black Locust trees of Ontario and Quebec are being so seriously injured 

 by the Locust Borer that it seems advisable to draw attention again to the available 

 means of control. The beetle and its habits are so well known, and have been so 

 thoroughly discussed in literature that only the briefest outline will be included 

 liere. *• 



The adult, a beautiful black and yellow-banded, long-horned beetle, slightly 

 over half an inch in length, emerges from the infested trees during August and 

 September, and is found feeding upon the pollen of goldenrod flowers, and laying 

 its eggs in crevices in the bark of living locust trees. The beetles were active at 

 Ottawa this season between August 14th and" September 17th. They were captured 

 upon a patch of goldenrod near the infested locusts, and in smaller numbers upon 

 the trunks of the locust trees. A larger area of goldenrod a few hundred yards 

 beyond the first yielded very few beetles. Apparently the beetles seek the nearest 

 goldenrod pollen, and were to be seen flying back and forth between the locust trees 

 and their feeding ground. 



The beetles are found crawling upon the bark of the locust trunks and 

 branches, mating and depositing eggs. The female searches with the very sensitive 

 ovipositor in the bark crevices until a suitable place is found, and deposits there an 

 elongate white egg, neatly and securely wedged into the crevice so that very little 

 of the egg is visible, and more safely attached by a mucilaginous secretion coating 

 the egg-shell. The larva emerges through the hidden end of the egg-shell, and 

 bores directly into the inner bark, leaving the egg-shell and the entrance tunnel 

 packed with castings. In the yellow living inner bark it excavates a small shallow 

 cavity within which it remains quiescent until the following spring. During the 

 dormant period of the trees the larvae are therefore very small, immediately 

 beneath the corky outer bark and with a short overlying mine connecting them with 

 the exterior. In the spring the larvffi extend their tunnels into the wood, 

 sometimes penetrating to the heartwood in branches or small trunks. The tunnels 

 are commonly lengthwise, and are always kept connected with the ^exterior by an 

 opening as large as the larva, through which the borings are thrust. When full 

 grown, late in July or in August, the larva enlarges the end of its tunnel, closes 

 itself in with chips, and changes to the pupa and then to the adult. The adult 

 beetle leaves the wood through the hole kept open by the larva. 



The injury to the trees caused by successive generations of larvre girdles the 

 trunks and branches partly or completely and kills the branches and areas of bark 

 on the trunk until finally the tree succumbs. Branches and trunks of the smaller 



