8 STATE BOARD OF AGRICULTURE. 



a beak. These creatures are able to puncture plant and other tissue 

 and to suck the juices, vegetable or animal, as the case may be. The 

 Parasitica contains those forms without wings, adapted to live among 

 the hair on the blood of certain vertebrates, and here the beak is not 

 developed or is lost, the piercing lancets being retractile into the 

 head. 



The order Homoptera, another of the divisions of the Rhyngota, 

 contains the plant lice, scale insects, leaf hoppers and mealy bugs, 

 hence is, in its entirety, injurious to the agriculturist. The wings 

 when they are present are always of similar texture throughout, 

 though the two pairs may not be alike. 



The Hemiptera have the upper pair of wings thickened at the 

 base and thin or membraneous at the tip, and this gives them the 

 name half-winged. They are the true "bugs" of the entomologist 

 and contain such forms as the "chinch bug," "squash bug," "bed 

 bug." The great majority of all these bugs are injurious to plant 

 life, though in some groups a predatory habit has developed. 



None of the Rhyngota have a true metamorphosis or transforma- 

 tion, though the males of the scale insects make an approach to it. 

 The little bug just out of the egg resembles its parents in all save 

 size, absence of wings and lack of sexual development. 



Taking it all in all the sucking branch of the insects is small com- 

 pared to that in which mandibles were developed, for the possession 

 of jaws or biting structures opened up a much greater range of food- 

 getting possibilities. 



With the development of wings the thoracic segments which bear 

 the organs of locomotion became modified. At first all the segments 

 were similar to each other, and one series retained this peculiarity, 

 all the rings being of practically equal importance. These are all 

 loose- jointed frail forms, with large transparent wings. 



A departure was made when the second and third segments which 

 bear the wings became united together for more compact muscular 

 attachments and the first segment or prothorax was left free. 



The highest specialization was reached when all three of the 

 thoracic segments united to form a compact body supporting all the 

 organs of locomotion. 



These different modifications once started tended to become intensi- 

 fied, and there is little difficulty now in recognizing the orders belong- 

 ing to each series. 



Perhaps the simplest type in general structure are the Isoptera, 

 including what are generally known as white ants. These creatures 

 are soft-bodied, loose-jointed, all the thoracic rings well developed, 



