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ENTOMOLOGY: BASIC ENTOMOLOGY [continued]

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  MG Manual Reference
Ch. 3, pp. 8 - 10
[ Basic Entomology: introduction | anatomy | development | classification | specific groups; coleoptera, lepidoptera, diptera, hymenoptera, hemiptera, homoptera, orthoptera, isoptera, dermaptera, thysanoptera, thysanura, collembola, other insects, relatives, other classes ]


SPECIFIC INSECT GROUPSTop

Major insect groups are called orders. There are between 27-30 orders depending on the authority you read, but some of the most common and economically important are:

Separating the groups of insects may be quite difficult unless you have closely studied examples of the various types. On the following pages are detailed lists of the characteristics of each order to help you distinguish between them.
Figure 5. The developmental stages of beetles

Eggs
Eggs

{short description of image}
Beetle Larvae (Grubs)

Pupa
Pupa

Adult
Adult

ORDER COLEOPTERA -- BEETLES AND WEEVILSTop

a. Adults with one pair of hardened outer wings (forewings) giving them a "shell-like" appearance, and an inner pair of membranous wings. (A few beetles are practically wingless, or lack the inner wings).
b. Beetles have chewing mouthparts.
c. Adults beetles have noticeable antennae.
d. Larvae are sometimes called grubs. They have a hardened head capsule, and 3 pairs of legs on the thorax. (Some weevil larvae lack legs).
e. Beetles undergo complete metamorphosis.
f. The order Coleoptera contains the most species of all the insect orders. Over 600,000 different species of beetles have been identified.
Some of the typical beetles that you may see are the long-horned beetles and flatheaded borers. The larvae are elongate grubs that bore into trees, logs, firewood, cacti, and lumber. The long-horned beetles are named for their long antennae as adults. Examples of long-horned beetles are the palo verde borer, and the cactus borer. Important beneficial species include the lady beetles, ground beetles, and tiger beetles. Lady beetles are about 1/4 inch long and are usually red or orange, generally with spots. Lady beetles are beneficial as larvae and adults, since they feed on aphids and other soft-bodied insect and mite pests. The agave weevil, which is a destructive pest of agave, also is a member of the order Coleoptera. Darkling beetles are dark-brown or black, sluggish beetles that occasionally become nuisance pests inside houses.
Figure 6. The developmental stages of the tomato hornworm

Eggs

Eggs

Larva
Larva

Pupa
Pupa

Adult
Adult

ORDER LEPIDOPTERA -- BUTTERFLIES AND MOTHSTop

a. Adults are soft-bodied with four well-developed membranous wings covered with small scales.
b. The larvae have chewing mouthparts, and are voracious feeders.
c. Adults have a coiled, sucking tube for feeding on nectar or no mouthparts at all.
d. The larvae are called caterpillars. They are worm-like in shape and some are quite colorful.
e. The larvae have three pairs of true legs on the thorax and a variable number of fleshy appendages called prolegs on the abdomen.
f. Insects in the order Lepidoptera undergo complex metamorphosis.
Butterflies have threadlike antennae with a knob at the end, and fly during the day. Moths often have feathery antennae, and fly to lights at night.
Some moths commonly found in the garden are cutworms, which feed on many crops. The corn earworm larva varies in color from greenish to tannish with lengthwise stripes, and it is about 1 1/4 inch long when fully grown. The cabbage looper is found on cole crops. The larva moves its rear end to meet its head as it crawls and loops foreword, giving it the name "looper."
Anyone who has grown tomatoes has encountered the tomato hornworm, which gets its name from the distinctive horn projecting from the rear. The adult moth is a few inches long and mottled gray to black with a few yellow bands on the sides of its abdomen. The adults are sometimes seen around flowers or hummingbird feeders at dusk.
Butterflies which may be found in yards include the beautiful black and yellow swallowtail called the orange dog. The larvae are brown, gray and white and mimic bird droppings. They are found on citrus leaves. In the spring, orange and black painted lady butterflies may be seen migrating through Arizona. Another butterfly found in yards is the gulf fritillary, the larvae of which feed on passion vines.

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