No. 6. DEPARTMENT OF AGRICULTURE. 387 



LIFE HISTORY OF THE INSECT. 



Before one can di'al intelligently with an}' insect, it is necessar}' to 

 know its life history and habits, that our eliorts may be intelligently 

 directed; therefore a brief description is here given. 



The full grown scale, when by itself on a twig, is almost circular in 

 shape and about one-sixteenth of an inch in diameter. It is black- 

 ish gray, the centre a little raised and dull yellow in color. It is not 

 at all conspicuous, especially on gray bark, and is very easily over- 

 looked. When grouped in large numbers the individual scales vary 

 a little in shape; but are always small, round, dark gray discs with a 

 yellow center. If, with the point of a knife we carefully lift one of 

 these scales we find lying free, underneath it, a much smaller, flat- 

 tened, bright yellow, soft bodied creature — the scale-insect itself. 

 This has neither legs, wings or other organs of locomotion and, in 

 fact, no appendages except three fine bristles which form the mouth. 

 These bristles are inserted into the plant tissue and by this means 

 the insect holds its place. In other words, there is a very small, 

 bright yellow, grub-like creature, covered by a scale of its own manu- 

 facture. 



A scale insect, such as described, is a female and, when mature, it 

 gives birth to living young. The period of reproduction extends 

 throughout a month or six weeks, and in that time an individual may 

 give birth to about 500 young. These young, or larvae, are minute 

 yellow atoms with short legs and feelers and are capable of motion. 

 On a badly infested tree, when the insects are breeding, the surface 

 will appear covered with moving pollen grains, so small are they. 

 Their bright color makes them conspicuous, and with a little practice 

 one may see them readily with the unaided eye. They move about 

 quite actively for such small creatures and usually tend outwardly, 

 to the smaller branches, fruit spurs, leaves, or to the fruit itself; in 

 fact, except on peach, the fruit is a favorite place. After about 

 twenty-four hours of this active life the larva finds a suitable place, 

 inserts the microscopic mouth bristles into the plant tissue, begins 

 to feed and is then a fixture. In a few hours it begins to contract 

 and becomes circular in outline, like a minute, yellow lentil. Then 

 little, white, cottony filaments come from specialized pores all over 

 the surface until the creature looks like a tiny lump of cotton. These 

 filaments or threads run together and form the first covering to the 

 fixed larva. In this stage the white color makes them easy to see; 



