Injurious insects occur among the following orders: Coleoptera, Hymenoptera, Lepidoptera, Diptera, Hemiptera (both heteroptera and homoptera), Orthoptera, Neuroptera and Thysanoptera.
In bugs (Heteroptera) and many flies, for example, they are changed into needle-like piercers (fig.
3, d), which is large and conspicuous in those insects, such as cockroaches, bugs (Heteroptera) and beetles, which have the prothorax free - i.e.
Heteroptera: Rostrum not in contact with haunches of fore-legs.
The Heteroptera can be traced back farther than any other winged insects if the fossil Protocimex silurica Moberg, from the Ordovician slates of Sweden is rightly regarded as the wing of a bug.
The order is divided into two suborders, the Heteroptera and the Homoptera.
Heteroptera In this sub-order are included the various families of bugs and their aquatic relations.
Most Heteroptera are flattened in form, and the wings lie flat, or nearly so, when closed.
It is usual to divide the Heteroptera into two tribes - the Gymnocerata and the Cryptocerata.
This tribe includes some eighteen families of terrestrial, arboreal and marsh-haunting bugs, as well as those aquatic Heteroptera that live on the surface-film of water.
In this tribe are included five or six families of aquatic Heteroptera which spend the greater part of their lives submerged, diving and swimming through the water.
In their life-history the Homoptera are more specialized than the Heteroptera; the young insect often differs markedly from its After Weed, Riley and Howard, Insect Life, vol.
14) forming an order distinct from the Hemiptera, their sucking and piercing mouth-organs being apparently formed on quite a different plan from those of the Heteroptera and Homoptera.
For internal structure of Heteroptera see R.
Among general systematic works on Heteroptera may be mentioned J.
Saunders's Hemiptera-Heteroptera of the British Isles (London, 1892); J.
Sound-producing organs of Heteroptera are described by A.