138 PROTECTION OF PLANTS, 1916-17 



NEAR RELATIVES OF INSECTS INJURIOUS TO PLANTS AND 



ANIMALS 



W. Lochhead, Macdonald College 



Crustaceans, Arachnidans and Myriapods belong to the great Branch 

 of Animals called the Arthropoda, hence are here termed near relatives of 

 insects. 



Class Crustacea 



Sow Bugs, Pill Bugs, or Wood Lice. — Sow bugs cause considerable 

 injury both indoors and outdoors to young growing flowers and vegetable 

 crops. They occur in dark moist conditions near dwellings, such as cellars, 

 outhouses, about walls, cisterns, water barrels, under boards, stones and 

 rubbish; in greenhouses and rockeries. They usually feed at night. Sow 

 bugs are sometimes injurious in mushroom beds. 



The eggs are laid in early summer. The incubation period varies with 

 the different species — in Armadillium vulgare Latr. about 70 days. The 

 young are carried in a pouch formed of modified plates on the abdomen of 

 the females. Other species are Porcellio laevis Latr., A. quadrifrons and 

 Oniscus asellu^ Linn. They have seven pairs of legs and antennae which 

 are seven-jointed. 



Control. — ^Cleanliness about outhouses, potting houses etc. ; the use of 

 baits of sliced potatoes covered with a thin coating of Paris green, or of 

 bran, Paris green, molasses, orange juice; sprinkling or spraying with 

 kerosene emulsion; sprinkling Paris green on the floor of greenhouses and 

 covering it with damp boards; trapping by means of inverted flower pots 

 containing damp hay or moss; flushing crevices, edges of greenhouse beds, 

 benches and ground beneath with hot water or steam; fumigation with 

 sodium or potassium cyanide {\-}/2 oz. of cyanide to every 100 cubic feet 

 of space.) 



Class Arachnida 



Order Acarina (Mites and r^'c^^.)— Abdomen unsegmented, sometimes 

 with annulations, without a deep constriction between cephalathorax and 

 abdomen ; legs usually well developed ; body more or less depressed. 



Chief Families and Genera 



Eriophyidae. — Elongated annulated forms. Eriophyes on plants. 

 Argasidae. — Argus, Ornithodoros, on birds. 



