Hemiptera Family- Pentatomidae, Coreidae, Pyrrhocoridae, Lygaeidae

Order - Hemiptera: Family- Pentatomidae, Coreidae, Pyrrhocoridae, Lygaeidae, Cicadellidae, Delphacidae, Aphididae, Coccidae, Lophophidae, Aleurodidae or Pseudococcidae

Order - Hemiptera

Synonym : Rhynchota

Etymology :Hemi - half; ptera - wing

Common name :True bugs

General characters

• Head is opisthognathous.

• Mouthparts are piercing and sucking type. Two pairs of bristle like stylets which are the modified mandibles and maxillae are present. Stylets rest in the grooved labium or rostrum. Both labial palps and maxillary palps are atrophied.

• Mesothorax is represented dorsally by scutellum.

• Forewings are either uniformly thickened throughout or basally coriaceous and distally membranous,

• Cerci are always absent.

• Metamorphosis usually gradual; rarely complete.

• Alimentary canal is suitably modified to handle liquid food. (filter chamber)

• Salivary glands are universally present,

• Extra-oral digestion is apparently widespread.

• Abdominal ganglia fused with thoracic ganglia.

Classification: There are two suboders viz., Heteroptera and Homoptera.

	Heteroptera (Hetero-different;ptera-wing)	Homoptera (Homo-uniform; ptera-wing)
1.	Head is porrect or horizontal	Head is deflexed
2.	Bases of the forelegs do not touch the head	Bases of the forelegs touch the head
3.	Beak  arises  from  the  anterior  part  of the	Beak  arises  from  the  posterior  part  of the

	head	head
4.	Gular region of the head(midventral sclerotised part between labium and foramen magnum) well defined.	Gular region not clearly defined
5.	Pronotum usually greatly enlarged.	Pronotum is almost alway small and collar- like.
6.	Scutellum (triangular plate found between the wing bases) well developed	Scutellum not well developed.
7.	Forewings heavily sclerotized at the base and the apical half is membranous (Hemelytra)	Forewings are of uniform texture. They are frequently harder than hind pair.
8.	Wings are held flat over the the back at rest and the left and right side overlap on the abdomen.	Wings are held roof-like over the back and wings do not over lap.
9.	Honey dew secretion uncommon	Honey dew secretion common
10	Repungnatorial or odori- ferous or scent glands present.	Wax glands usually present.
11.	Both terrestrial and aquatic	Terrestrial.
12.	Herbivorous, predaceous or blood sucking.	Herbivorous.

Important families of Heteroptera (Hetero-different;ptera-wing)



LYGAEIDAE (Seed bugs or Chinch bugs) - family

• Cuneus is absent in hemelytra.

• Membrane has a few irregular veins (4-5 veins) arising from a transverse basal vein.
  

e.g. Dusky cotton bug Oxycarenus hyalinipennis nymphs and adults suck the sap from seeds of injured or already opened bolls and reduce the seed quality.

PYRRHOCORIDAE (Red bugs or Stainers)-family

• They are elongate oval bugs.

• They show warning colouration. They are brightly marked with red and black.

• Membrane is with more branched veins and cells. e.g. Cotton stainer Dysdercus cingulatus.

• Feeding   injury  caused  by  these  bugs   leads  to  the  contamination  by  the     fungus

Nematospora resulting in yellowish brown discolouration of the lint.

 

COREIDAE (Squash bugs or leaf footed bugs)- family

• Membrane with many branching veins arising from a transverse basal vein.

• Stink glands are found inside the metathorax and glands openings are found on the sides of the thorax between middle and hind coxae. They emit a bad odour.

• Hind tibia and tarsi are expanded and leaf like.

• The edge of the abdomen is raised and wings lie in a distinct depression.e.g. Pod bug,

Riptortus pedestris nymphs and adults suck the sap from pods of pulses.

 

4. PENTATOMIDAE (Stink bugs or Shield bugs) - family

• Antenna is five segmented.

• Scutellum is prominent and shield like.

• Adults and nymphs produce a disagreeable odour from stink glands located in metathorax and abdomen respectively.

• Some are phytophagous and some are predaceous. e.g. Green stink bug Nezara viridula is a pest on millets.



 

Important families of Homoptera (Homo-uniform; ptera-wing)

CICADELLIDAE (Leaf hoppers or Jassids)

• Elongate insects with a wedge shaped body.
• Attractively coloured.
• Hind tibiae have a double row of spines.
• Ovipositor is well suited for lacerating the plant tissue.
• Nymphs and adults have the habit of running sidewise.
• They suck the plant sap and transmit diseases. eg. Green leaf hopper Nephotettix virescens transmits tungro disease in rice.

DELPHACIDE (Plant hoppers)

• Large mobile flattened spur is present at the apex of hind tibia

• eg. Brown plant hopper Nilaparvata lugens causes hopper burn, transmits viral diseaes in rice.

LOPHOPHIDAE

• Head is produced into a snout.

• Hind trochanter is directed backward

• Hind basitarsus is moderately long. e.g. Sugarcane leaf hopper Pyrilla perpusilla nymphs and adults suck the sap and reduce the quality and quantity of cane juice.

ALEURODIDAE (Whiteflies)

• Minute insects which superficially resemble tiny moths.
• Wings are opaque and dusted with mealy white powdery wax. Wing venation is much reduced.
• Vasiform orifice is present in the last abdominal tergite. It is a conspicuous opening provided with an operculum. Beneath the operculum there is a tongue-like organ termed lingula. The anus opens at the base of the lingula through which honey dew is excreated in large amount.
• Immature instars are sessile, scale like, with waxy covering.
• Metamorphosis approaches the homometabolus type due to the presence of a quiescent stage prior to the emergence of adults.
• e.g. Cotton whitefly Bemisia tabaci transmits vein clearing disease in bhendi.

APHIDIDAE (Aphids or Plant lice or Greenflies)

• Body is pear shaped
• Both apterous and alate forms are found.
• A pair of cornicles or siphonculi or wax tubes is present in the dorsum of fifth or sixth abdominal segments which secretes wax like substance.
• They excrete copious amount of honey dew on which ants feed and sooty mould fungus grows.
• Aphids are known for their extraordinary fecundity, short life cycle and parthenogenitic reproduction. Life cycle is highly complex and it involve alternation of generation.
• They feed on plant sap and disseminate plant diseases.
• e.g. Cotton aphid Aphis gossypii.

COCCIDAE (Scale insects or Soft scales)

• Sexual dimorphism is present.
• Male : They are gnat like, with long antennae, lateral eye and vestigeal mouth parts.
• Mesothorax is enlarged bearing one pair of wings with on or two veins. Hind wings are reduced to halteres. A quiescent stage is present in the life history.
• Female : Body segmentation is indistinct. Body wall naked and covered with a waxy coating. They are wingless, legless and suck the plant sap.
• The first instar nymph is active and is known as crawler which moults and becomes legless. e.g. Coffee green scale Coccus viridis.

PSEUDOCOCCIDAE (Mealy bugs)

Body is elongate oval in shape.
Body segmentation is distinct.
Body is covered by long radiating thread of mealy secretion.
Functional legs are present in all instars.
Wings are absent.
e.g. Coconut mealy bug, Pseudococcus longispinus.
Nymphs and adults suck the sap and affect the growth of spindle leaf.