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 José scale (Aspidiotus 
perniciosus) because it was accidentally introduced 
at San Jose, Calif. Scale insects in feeding suck 
the juices from many kinds of plants. The San 
José 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 Flcure 43. Scale in- 
the first few hours of its hfe, 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. 
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- 
gens). 
FIGURD 44. — Lady- 
beetle. 
