HEMIPTERA. 163 



be dissolved and washed down by the rains. This will serve 

 to destroy certain other pests, as well as the woolly aphis 

 In case it is desired to rid an infested tree of this pest, the 

 trunk form should be washed off with a strong solution of 



o 



soap applied with a sponge, taking care to destroy all eggs ; 

 and the ground should be treated with carbon bisulphide, as 

 for the Grape Phylloxera. 



Family ALEYROPID.E (Al-eu-rod'i-dse). 

 TJie A ley r odes (Al-cu-ro' des). 



The insects of the genus Aleyrodcs were for a long time 

 classed with the Coccidae. In their immature state they are 

 scale-like in form (Fig. 200), and often somewhat resemble 

 certain species of Lecanium. But the 

 mature insects differ so much from the 

 Coccids that the genus has been sepa- 

 rated as a distinct family. They are very 

 small insects; the species with which I 

 am acquainted have an expanse of 

 wings of about one eighth of an inch. 

 Both sexes are winged ; and, as with 



. , TT .1 / -j FIG. 200. Aleyrodet 



other Hemiptera except the Loccids, 



there are two pairs of wings. In the adult state, all the 

 species are nearly of the same color ; the wings are white, 

 sometimes spotted ; the body is usually yellowish, sometimes 

 pinkish, and more or less spotted with black. The most 

 striking character presented by the adults, in addition to the 

 fact that both sexes are winged and each has two pairs of 

 wings, is the presence of a whitish powder with which the 

 wings and body are covered. It is this character that 

 suggests the name of the genus, which is from the Greek 

 aleurodes, like flour. 



