ly Saperda Candida in District of Quebec. 281 



Emmons, is conclusive evidence that the deposition of the eggs 

 was attended with congenial weather. Any person who has 

 studied the hahits of forms constituting the Longicorn family, will 

 hold with me as to the strong parasitical attachment of the parent 

 insects to their favourite plants, while propagating their species ; 

 and we have hundreds of instances where insects only take a few 

 weeks to complete their stages, being some years scarce, while at 

 other times so common as to overrun the country. 



The Saperda Candida or apple-tree borer, becomes perfect in 

 the neighbourhood of Quebec, on the 9th of June, and continues 

 to issue from the trees up to the 12th or longer ; therefore, the 

 trees should be carefully examined and protected as hereafter 

 specified, during the whole of the above month. The insect in- 

 variably deposits its eggs at the base of the tree, where it enters 

 the earth ; the larva cuts its way obhquely upwards, cross-cutting 

 the circulation of the sap, and depriving it of its nourishment. 



The following instructions should be carried out to ensure suc- 

 cess in exterminating the borer : — 



1. Import no more young apple-trees from the United States, 

 without a thorough examination for the larva. It would be pre- 

 ferable to obtain them from the Upper Canada nurseries where 

 the insect does not occur. 



2. Mix an earth-mortar or clay such as is used for grafting 

 purposes, and with it surround the lower part of the tree, say 1^ 

 or 2 feet. It should have a thickness of Ij- or 2 inches, and 

 made to adhere closely to the earth where the trunk enters it. 

 Apply it also from the 1st of June to any of the attacked trees 

 showing symptoms of life. If there are any perfect insects to 

 issue, escape will be cut off, and much good done in this way. 

 It is useless to use solutions of any kind, as the larva ascend the 

 tree and will remain untouched. 



3. It would be advisable to use the same precaution with pear 

 trees during this period, as the apple-borer may select them when 

 deprived of its more congenial tree. 



ARTICLE XXYIII. — Discovery of Microscopic Organisms in 

 the Siliceous Nodules of the Palceozoic Rocks of New York, 



At Prof. Dana's suggestion, Dr. M. C. White, well known for 

 his devotion to the microscope, has examined various specimens 

 of the hornstone nodules found in the Devonian and Siluriaa 



