ONION INSECTS. The principal insects which damage the onion crop are the onion-mag got (larva of Phorbia eepareni). the onion thrips (Thrips tritici), and the onion-cutworm (larva of Agrotis nicssoria ). The adult of the onion-maggot is a fly of the family Anthonlyiid.e. The eggs are laid early in the spring, next to the stems or leaves at the surface of the ground, and preferably in young onion beds. The larvae work their way into the bulb and cause the rapid de cay and death of the plant. Inasmuch as the bulb is the edible part of the vegetable. the slightest damage by these maggots is fatal, since the decay continues even after the maggots are killed. The maggots reach full growth about the end of May, and about the middle of June the second generation of flies occurs. This gen eration often attacks seedling onions, ruining entire beds. The insect passes the winter partly in the pupa state in the ground. and partly as adult in sheltered locations. On a small scale damage may be prevented by the use of sand soaked in kerosene, mixed with drier sand and placed at the base of the onion plants along the rows. This prevents egg-laying and kills such of the young maggots as attempt to work through it. On a large scale. the first plants which wilt must be lifted out and destroyed, and then kainit and nitrate of soda must be applied broad cast to the roots.
The onion-thrips sometimes attacks onions in great numbers, puncturing the succulent leaves and leaving a small dot after each punc ture. The leaf gradually loses it vitality and the top turns yellow. This thrip: is not con• fined to the onion. hut is also found upon cab bage: and the flowers of the orange farther South, In 1898 the product readied 8,300,000 pounds, over half of which was into the United States. Iron is found in the same region as cop per, and also in the region north of Kingston.
An adverse tariff had prevented mining opera tions until recently, when the province placed a bounty upon its production. Since that time the industry has rapidly The product for 1899 was estimated at. $850,000.
Gold has been found at points along the entire length of the Archaean rocks of the province. it is in the most paying quantities, however, in the region west of Lake Superior. The gold lies in quartz veins, and only recently has its exploita tion been seriously undertaken. The annual value of the product increased during 1890 to 1900 from nothing to $421,000. Silver is mined on the west shore of Lake Superior, but its pro duction is small and uncertain. Prior to 1890 the principal mineral productions were secured from the older portion of the province. and con sisted of petroleum and salt. Petroleum is found at the south point of Lake Huron in Lambton County. The average annual product from 1890 to 1900 exceeded 30,000,000 gallons. Farther north along the east shore of Lake Unroll are the salt beds, whose annual yield from 1890 to 1900 averaged over $200,000. Dur ing the last decade, the mineral wealth of peninsular Ontario has been increased by the development of natural gas fields near Niagara in the east and near Detroit in the west. The product of the latter field is consumed by the city of Detroit, and that of the former by the city of Buffalo. The estimated annual value of the product since 1893 has been $350,000. Clay for brick and tile occurs in all parts of the province. Limestone and sandstone for building purposes abound in the Paleozoic region, and granite and marble are quarried in the region.