ENTOMOLOGY 109 



vening dam. Other heath plants are also undesirable and should 

 not be allowed too near the bogs nor on the dams. 



(7) It follows from what has been said that the bog itself 

 should be kept as free as possible from all plants other than vines, 

 certain grasses being especially objectionable because they are used 

 by long-horned grasshoppers as places to lay their eggs. 



Bogs so arranged could be kept completely safe at all time, 

 and once properly laid out would require little outlay to keep them 

 so. The question whether bogs should be kept wet or dry, whether 

 there should be many or few ditches, and whether these should be 

 deep or shallow need not be here considered at all. The dates of 

 flowage and reflowage and other points of measurement by means 

 of which control may be made effective have been already touched 

 upon. 



The important advantages are that neither insecticides nor 

 spraying machinery would ever be required, and the insect prob- 

 lem would be reduced to the simplest possible terms. (Farmers' 

 Bui. 178 U. S. D. A.) 



SCALE INSECTS AND MITES ON CITRUS TREES. 



THE ARMORED SCALES. 



The majority of the important scale-insect enemies of the orange 

 belong to the group known as armored scales because the insects be- 

 gin to excrete as soon as they, thrust their beaks into the tissues of 

 the plant a waxy covering which protects the growing insect and 

 forms a definite scale-like shield entirely independent of the insect 

 itself. This group includes the long scale, purple scale, the red scale 

 of California and the red scale of Florida (an entirely distinct in- 

 sect), the oleander scale, the chaff scale, and other less important 

 species. 



In general habits these armored scales are very similar. The 

 eggs, which are developed in enormous numbers, may be extruded 

 under the covering scale of the mother insect and undergo a longer 

 or shorter period of incubation before hatching, or the young may be 

 partly or fully developed within the body of the mother and emerge 

 as active insects, or more properly shake off the egg envelope at the 

 moment of birth, so that certain species appear to yield living young. 

 The young of these different species of armored-scale insects very 

 closely resemble each other, and can not be distinguished without 

 careful microscopical study. While very minute, the young are yet 

 visible to the naked eye, and during the breeding season may be seen, 

 by sharp inspection, running about on the leaves, twigs, and fruit. 

 In color they are usually light lemon-yellow, They have six well- 

 developed legs, also antennae and eves, and are highly organized in 

 comparison with the degraded condition soon to be assumed. After 

 finding a suitable situation, often within a few minutes from the 

 time of their emergence, though sometimes not for an hour or two, 

 they settle down, thrust their long slender hair-like beaks into the 

 plant, and immediately begin growth, the first evidence of which is 

 the secretion of waxy filaments from the upper surface of the body, 



