1902.] INSECTS — RELATION TO AGRICULTURE. 20I 



At first the insect is provided with legs, and antennae, 

 eyes and mouth parts, and shortly after it settles upon the 

 bark a number of white waxy filaments are thrown out upon 

 its back, and these melt down and the insect casts its skin. 

 These filaments, together with the cast skin, form the ex- 

 ternal covering of the scale. Soon after this the legs and 

 antennae disappear. The insect also loses its eyes. The 

 mature female has no legs, eyes, antennae, but has the mouth 

 parts and reproductive organs very strongly developed. With 

 the male insect these organs do not all disappear, but the 

 adult goes forth with very large antennae, and with wings, 

 legs, and eyes. He has, however, no digestive system, and 

 therefore cannot take food. The shell or armor of th^ male 

 differs from that of the female in being elongated, with the 

 nipple near one end. When mature the male comes forth 

 from under the shell and flies away. 



The insect passes the winter in a half-grown state, and 

 does not begin to reproduce until the last of June in this 

 latitude. After that the females continue to bring forth living 

 young for a period of about six weeks and then die. These 

 young reach maturity in about a month, w^hen they also pro- 

 ceed to reproduce, and, as the season advances, the number 

 of young increases. During the first of the season less than 

 150 young are born from each female, but late in the fall, 

 however, a single female has been known to give birth to 

 nearly 600 young. This gives us some idea of the remark- 

 able reproductive powers of the species. 



It is necessary to use drastic measures in fighting so seri- 

 ous a pest. Orchardists are now spraying their trees with 

 undiluted crude oil, with kerosene mixed with water in vari- 

 ous proportions, and with whale oil soap, two pounds in one 

 gallon of water. The cheapest remedy is kerosene mixed 

 with water by means of a pump made for the purpose. 

 Twenty to twenty-five per cent, of kerosene will scale if ap- 

 plied just before the leaves come out in the spring. It must 

 be used on a bright clear day or there will be danger of in- 

 juring the trees. Crude oil has this advantage, that it remains 

 on the tree for several months, making it nearly impossible 

 for the young insects to establish themselves upon the bark. 

 Whale oil soap is rather difficult to dissolve and to spray in 

 the proportions named, and it thickens very quickly upon 

 cooling. 



