54 



wings. The larva is about one hundredth of an inch long, minute, 

 active, with six legs. 



The eggs resemble white dust, and are almost microscopical. 

 Numbering up to eighty, they are laid under the female scale. 



In early summer, the six-legged larvae appear and, crawling from 

 beneath the scale, may be carried from tree to tree by wind, birds, 

 or certain insects, such as the lady-birds. 



In a few days they fix themselves to the plant by means of their 

 short proboscis, and suck away the juices. The scale soon forms from 

 a few waxy threads being excreted, and during this time the larva 

 becomes legless and fleshy. 



At the end of summer the female lays her eggs and dies, leaving 

 her shrivelled skin beneath the scale. 



If the larva is to become a male insect, which is very rare, a 

 different scale is produced and a different mature insect appears. 



The larva of a male undergoes a kind of pupal stage, after which 

 the winged form appears. 



Insecticides. Spray with the caustic winter wash, before given 

 as a good wash. Also steep 2 Ib. of tobacco for several hours in 

 9 gallons of water, and dilute this according to the quantity of scale 

 you have, and spray with this in June. 



If, however, the pest is very bad, fumigate the trees with hydro- 

 cyanic acid gas, using a tent over the tree, as before explained. 



5. THE OYSTER-SHELL BARK LOUSE, Aspidiotus ostreaeformis. 

 ORDER RHYNCHOTA. 



This insect also attacks the pear, plum, cherry, and currant. It 

 resembles very much the former insect as to the formation of the 

 " scale." The female scale attains a diameter of one twelfth of 

 an inch, being round, smooth, and rather flat. The central part 

 of the scale is dark, the rest being of a yellowy-brown colour. If 

 overcrowding occurs, the scales are much smaller. 



The adult female is flat, round, and yellow, and is devoid of eyes, 

 legs, and wings, with only rudimentary antennae. 



The male scale is much smaller, being about one twenty-fifth of 

 an inch in diameter. The adult male is orange-yellow in colour, with 

 a dark band across the thorax. It has antennae, legs, and two 

 wings, but is devoid of a functional mouth. The male pupa has 

 no mouth organs, but has antennae, legs, and signs of wings; it is 

 yellow, with black eyes and ocelli. 



In the second stage of the male and female, the insects are without 

 wings or legs, and remain attached to the bark by their rostra. 



The larva from the egg is quite minute, but active, with one pair 

 of jointed antennae of six joints, six legs, and a sucking mouth. 



The winged males appear in May, and by that time the females 

 are adult. 



The eggs are laid, and very soon the larvae hatch out and wander 



