Series Sternorrhyncha Phytophthires

Antennae long and thread-like, without a distinct arista (but apical segment often with a narrow terminal process); rostrum appearing to arise from between the forelegs; tarsi 1- or 2-segmented. Includes several groups of agricultural or horticultural significance.

Superfamify PSYLLOIDEA jumping plant-lice)

Very active, cicada-like bugs with the hindlegs strongly developed and adapted for jumping; front of head often with a pair of forwardly projecting genal cones; antennae 10-segmented; hindwings small, thinner and more membranous than forewings.

13. Family PSYLLIDAE (psyllids)

Adult forewings rounded apically, vein M + Cu present (Fig. 33a). Nymphs relatively broad-bodied; wing pads rounded (Fig. 34).

Fig. 34 Nymph of a psyllid, Psylla sp. - family Psyllidae (x25).

EXAMPLES: Psylla mail (apple sucker), Psyllopsis fraxini (ash leaf gall sucker).

14. Family TRIOZIDAE (p. 103)

Adult forewings angular apically, vein M + Cu absent (Fig. 33b). Nymphs relatively narrow-bodied; wing pads angular.

EXAMPLE: Trioza apicalis (carrot sucker).

Superfamily ALEYRODOIDEA (whiteflies)

15. Family ALEYRODIDAE (whiteflies)

Small, moth-like insects more or less coated with an opaque, white, waxy powder; antennae 7-segmented; wings soft, rounded and with a reduced venation (Fig. 35); tarsi 2-segmented. Nymphs fiat and scale-like. Development includes a quiescent, scale-like, non-feeding pseudo-pupal stage. The insects, especially nymphs, excrete vast quantities of honeydew. EXAMPLE: Aleyrodes proletella (cabbage whitefiy).

Superfamily APHIDOIDEA (aphids)

Insects with often complex life histories, the various groups most readily distinguished by features of the 1- to 6-segmented antennae, the siphunculi and the cauda (Fig. 36); tarsi 2-

Fig. 35 Wing venation of a whitefly - family Aleyrodidae.
Fig. 36 General structure of an apterous aphid -superfamily Aphidoidea.
The Body Structure Aphids
Fig. 37 Antennae of aphids: (a) family Lachnidae; (b) Chaitophoridae; (c) Pemphigidae.

root aphid), Tuberolachnus salignus (large willow aphid).

17. Family CHAITOPHORIDAE

Aphids with the body and legs bearing long hairs; terminal process of antennae very long (Fig. 37b); siphunculi pore-like or stumpy; cauda knob-like or rounded; Rs vein of forewing present.

EXAMPLES: Chaitophorus beuthani (osier leaf aphid), Periphyllus californiensis (Californian maple aphid).

18. Family DREPANOSIPHIDAE

segmented, each with a pair of claws; wings, when present, membranous.

16. Family LACHNIDAE

Aphids with the terminal process of the antennae very short (Fig. 37a); siphunculi usually short, very hairy cones; cauda broadly rounded; Rs vein of forewing present (see Fig. 39), Cu1 and Cu2 veins usually noticeably divergent.

EXAMPLES: Cinara pilicornis (brown spruce aphid), Maculolachnus submacula (rose

Aphids with the terminal process of the antennae of variable length; siphunculi usually stumpy or broadly conical but sometimes pore-like or long and swollen; cauda knob-like or rounded; subanal plate prominent, often divided into two lobes (Fig. 38); Rs vein of forewing present. EXAMPLES: Eucallipterus tiliae (lime leaf aphid), Phyllaphis fagi (beech aphid).

19. Family APHIDIDAE (aphids)

Aphids with the terminal process of the antennae of variable length; compound eyes multi-

Sternorrhyncha Alate

Fig. 38 Cauda and bilobed subanal plate - family Drepanosiphidae.

cauda

Fig. 38 Cauda and bilobed subanal plate - family Drepanosiphidae.

Sternorrhyncha Alate
Fig. 39 Venation of an alate aphid - family Aphididae.

faceted; siphunculi varying from short to very long cylinders, sometimes noticeably tapered or swollen and often flanged apically; cauda broadly tongue-shaped to finger-shaped; Rs vein of forewing present, forewings and hindwings with Cut and Cu2 and origins of these veins well separated (Fig. 39). Many species show an alternation of generations, having a primary (winter) host upon which asexual and sexual reproduction occurs and eggs are laid, and a secondary (summer) host upon which development is entirely asexual, parthenogenetic and viviparous. Migration between these alternate hosts is usually achieved following the production of winged forms. Aphids are commonly known as 'blackflies' or 'greenflies'.

EXAMPLES: Aphis fabae (black bean aphid),

Brevicoryne brassicae (cabbage aphid),

Bean Brassicae
Fig. 40 Venation of an alate aphid - subfamily Pemphiginae.

Myzus persicae (peach/potato aphid),2 Rhopa-losiphum padi (bird-cherry aphid), Sitobion avenae (grain aphid).

20. Family PEMPHIGIDAE (p. 121 et seq.)

Aphids with the terminal process of the antennae short (Fig. 37c); antennae of winged forms often (e.g. subfamily Pemphiginae) with annu-lated segments (Fig. 40); compound eyes reduced to three facets; siphunculi stumpy cones, pore-like or absent; cauda broadly rounded; body often with groups of well-developed wax glands; venation varies according to subfamily but Rs vein of forewing present and origins of

2 For many years, common names of certain heteroecious species of aphid (i.e. those with different winter and summer host plants) have included reference to both kinds of host, separated by a hyphen, that of the primary (winter) host having priority (e.g. willow-carrot aphid). This introduces potential confusion with common names hyphenated for other reasons (e.g. bird-cherry aphid). In recognition of this problem, some authors have used either an 'em' or an 'en' dash between the alternate host names but this subtlety is not always followed, probably being largely overlooked or misunderstood. In view of these difficulties, and to avoid ambiguity, a solidus (forward slash) is used in the present work to delineate primary and secondary hosts in such common names.

Fig. 41 Antenna of an alate aphid - subfamily Pemphiginae.
Fig. 42 Venation of an alate adelgid - family Adelgidae.

Cu1 and Cu2 veins on forewings and hindwings close-set and noticeably divergent: subfamily Pemphiginae - venation of forewing reduced (Fig. 41) (cf. Fig. 39). Associated primarily with trees and shrubs, often forming galls, but some species migrating in summer to herbaceous plants or grasses, including certain crops.

EXAMPLES: Eriosomatinae - Eriosoma lanigerum (woolly aphid); Pemphiginae -Pemphigus bursarius (lettuce root aphid).

21. Family ADELGIDAE

Entirely conifer-feeding, aphid-like insects; unlike true aphids, antennal segments short and wing venation reduced: Rs vein of forewing absent; hindwings often with just one, unbranched vein (Fig. 42); siphunculi absent; females entirely oviparous and covered in flocculent masses of wax; alates with five antennal segments. Life-cycles are very complex, often involving a variety of different morphs and alternation of host plants.

EXAMPLES: Adelginae - Adelges abietis and A. viridis (spruce pineapple-gall aphids); Pineinae - Pineus pini (Scots pine adelges).

22. Family PHYLLOXERIDAE (phylloxerans) (p. 123)

A small group of insects, structurally similar to adelgids but alates with just three antennal segments and wings held flat when in repose; wax (if present) never flocculent.

EXAMPLES: Viteus vitifoliae (grape phylloxera), Phylloxera glabra (oak leaf phylloxera).

Superfamily COCCOIDEA (scale insects)

A diverse group, demonstrating considerable sexual dimorphism. Larsi, if present, usually 1-segmented and with a single claw (cf. superfamily Aphidoidea). Males often rare or absent; if present, typically short-lived, small or minute; mouthparts vestigial; apterous or with just one pair of wings; body often terminates in a caudal spine and a longer pair of cerci (Fig. 43). Adult females wingless, usually sedentary and apodous; often scale-like or cushion-shaped. First-instar nymphs (crawlers) (Fig. 44) often very mobile, later instars usually becoming more or less sedentary. Many species excrete considerable quantities of honeydew.

23. Family DIASPIDIDAE (armoured scales)

Body of female protected by a hard, scale-like (often more or less circular or mussel-shaped) covering (Fig. 45a) formed from wax and cast-off nymphal skins; legs absent; hind segments of body fused to form a pygidium (Fig. 45b). Male scales (if present) typically smaller and narrower than those of females, and often distinctly ribbed longitudinally.

EXAMPLES: Aulacaspis rosae (rose scale), Lepidosaphes ulmi (mussel scale).

Scale Male Plants Symptoms
Fig. 43 Adult male of a scale insect, Pulvinaria ribesiae - superfamily Coccoidea (x35).

Fig. 44 First-instar nymph of a scale insect, Lepidosaphes ulmi - superfamily Coccoidea (xlOO).

Fig. 45 A scale insect, Lepidosaphes ulmi - family Diaspididae: (a) adult female scale (xf 5); (b) ventral view of adult female (x30).

Fig. 44 First-instar nymph of a scale insect, Lepidosaphes ulmi - superfamily Coccoidea (xlOO).

Fig. 45 A scale insect, Lepidosaphes ulmi - family Diaspididae: (a) adult female scale (xf 5); (b) ventral view of adult female (x30).

24. Family COCCIDAE (soft scales)

Body of female cushion-shaped and protected by an often tortoise-shaped, flexible or rigid, waxen scale; legs present or absent. Development often parthenogenetic. Male scales (if present) similar in appearance to those of females but usually smaller and narrower.

EXAMPLES: COCCUS hesperidum (brown soft scale), Parthenolecanium corni (brown scale), Pulvinaria regalis (horse-chestnut scale).

25. Family PSEUDOCOCCIDAE (mealybugs) (p. 125 et seq.)

Small to medium-sized insects; males rare and in many species unknown. Females elongate-oval and superficially woodlouse-like, with distinct body segmentation and relatively well-developed legs, but with poorly developed antennae; body more or less covered by a flocculent or mealy, waxen secretion.

EXAMPLES: Pseudococcus affinis (glasshouse mealybug), Rhizoecus falcifer (root mealybug).

Order THYSANOPTERA (Thrips)

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