]:!() ORDER HEMIPTERA 



ment to the surface of the bark. • This often lifts the scale 

 from the surface of the bark. There are distinct differences 

 in the markings of the body and in the anal plates. A rather 

 destructive form occurs on greenhouse plants, and is known 

 commonly by the name of "white fly." In some instances 

 it is very destructive. The eggs of the adults are laid on the 

 leaves and the larva? fix themsehes after a short migration 

 and develop until they have reached the pupal stage, and 

 from this stage the adult winged form issues. The family 

 is not so large nor so important as the scale insects — Coccidoe. 

 Two species occur on oranges in Florida; one, the orange 

 white fly, is often the means of serious loss in orange orchards. 

 They are treated by sprays and by culti\'ation of certain 

 parasitic fungi. 



COCCID^. 



The Coccidoe, scale insects, or bark lice, are to be considered 

 as the extreme branch along the line of specialization found 

 in this group. There are se^•eral subdiN'isions with various 

 kinds of specializations. The group is characterized by the 

 absence of wings in the females and the reduction of wings 

 in the males to one pair, they are usually firmly attached 

 to the plant on which the larva has settled and even in 

 forms not attached probable means of migration are limited. 

 The males are winged but show distinct specialization in 

 the reduction of the second pair of wings. These constitute 

 simple, aborted, hook-like structures that can serve no pur- 

 l)ose in flight. The same kind of reduction as in Diptera. 

 'Jlie males also show a fairly distinct metamorphosis. The 

 larvse change to a quiescent pupal stage and this gi\es rise 

 to an adult two-winged male. The females are wingless 

 and usually immo^'able, mating depends entirely upon the 

 migration and flight of the males. 



Owing to the extent and the economic importance of this 

 grou]), it seems desirable to give some account of the sub- 

 families and to discuss somewhat in detail certain of the 

 especially important economic species. Their sedentary 

 habits permit a ready distribution, yet make it easy to 



