4-H CLUB INSECT MANUAL 



19 



crawl. They prefer warm weather and spend the winter in all stages 

 on the host plant. The life changes are incomplete. Mealybugs 

 often become serious pests, but can be controlled by washing the host 

 with water under pressure, or by contact spray or fumigation, de- 

 pending on the plant on which they are feeding. The common 

 mealybug (Pseudococcus adonidum) is the one shown here. It is 

 about three-sixteenths of an inch in length. 



Scale insects. — Practically every person longs for a house in which 

 he can eat and sleep and possibly rest, but certain tiny insects 

 build a house in which they spend their entire life. Scale insects 

 are the ones referred to. Many people have seen the little houses, 

 about one-eighth of an inch wide, under which the insects live, 

 but few have ever seen the insects themselves because they are 

 so tiny. The shape or style of the house often assists in distin- 

 guishing the name of its inhabitant. For instance, there is an in- 

 sect which builds a house somewhat resembling a tiny oystershell, 

 and for this reason it is called the oystershell 

 scale. The scale insect pictured here, which 

 always presents the appearance of a small nipple, 

 is called the San Jose scale (Aspidiotus 

 pemiciosus) because it was accidentally introduced 

 at San Jose, Calif. Scale insects in feeding suck 

 the juices from many kinds of plants. The San 

 Jose scale spends the winter on its host plant and 

 attempts to live over in all stages, but most of 

 the survivors are second-stage nymphs. During 

 the first few hours of its life, the young scale 

 insect crawls about on the plant, but soon settles down and starts 

 to secrete a scalelike covering. Once established, the female never 

 leaves the scale. The male insects, however, have wings and come out 

 at certain seasons of the year, depending on the locality. Scale 

 insects become very destructive at times. Some are controlled by 

 contact sprays and others by fumigation. 



Figure 43. — Scale in- 

 sect. 



COLEOPTERA (BEETLES) 



One of the largest orders of insects is the Coleoptera to which 

 belong the beetles, all of which have complete life changes. They 

 usually have leathery forewings, and the hind wings when present 

 and not in use are folded up under these leathery wings. Many of 

 the beetles are severe pests. 



Ladybeetles. — Very common representatives of this order are the 

 ladybeetles. However, most ladybeetles are beneficial because they 

 feed on other insects. The species vary widely in 

 color, are usually spotted, and have a somewhat 

 oval body about one-fourth of an inch long. Lady- 

 beetle larvae are somewhat lizardlike and usually 

 have short tufts of spines over the body. These 

 insects abound in colonies of plant lice. They over- 

 winter in the adult stage ; their four life stages are 

 spent above ground. The little friend shown here 

 is the convergent ladybeetle (Hippodamia conver- 

 gent) . 



Figueb 44. — Lady- 

 beetle. 



516678° — 43- 



