Agriculture Reference
In-Depth Information
ORDER THYSANOPTERA (THRIPS)
Minute or small, slender-bodied insects with a
distinct head, a well-developed prothorax and a
long, narrow, 11-segmented abdomen (the first
segment greatly reduced and the last modified in
association with the external genitalia); cerci ab-
sent; wings, when present, very narrow, membra-
nous and strap-like, with few or no veins and
marginal fringes of long setae; antennae short, 6-
to 10-segmented; tarsi 1- or 2-segmented, each
with a protrusible terminal vesicle (the arolium).
Mouthparts asymmetrical and adapted for pierc-
ing. Metamorphosis gradual; development inter-
mediate between that of hemimetabolous and
holometabolous insects, and including an egg,
two nymphal and two or three inactive stages
(propupae and pupae); 3 nymphs similar in ap-
pearance to adults but wingless, less strongly
sclerotized and with fewer antennal segments;
the non-feeding propupae (Fig. 46) and pupae
have conspicuous wing pads, and lack the tarsal
vesicles found in nymphs and adults; in pupae,
the antennae are folded back over the thorax.
and with several cross-veins (Fig. 48), antennae
usually 9-segmented, body not flattened and
ovipositor curving upwards; wings often colour-
banded. Includes both phytophagous and preda-
tory species.
EXAMPLE: Aeolothrips tenuicornis (banded-
wing flower thrips).
2. Family THRIPIDAE (p. 90 et seq.)
A large and important group of sap-feeding
thrips, including many injurious species; the
Suborder TEREBRANTIA
Thrips with a saw-like ovipositor; tip of abdomen
conical in female (Fig. 47a), bluntly rounded
in male; wings typically bearing numerous
microtrichia; forewings with at least one longitu-
dinal vein extending to the apex. Development
includes egg, two nymphal and single propupal
and pupal stages. Eggs soft-shelled and usually
more or less reniform.
1. Family AEOLOTHRIPIDAE
(banded thrips) (p. 89 et seq.)
Fig. 46 Propupa of a thrips - family Thripidae.
Similar to members of the family Thripidae
(q.v.) but forewings usually rounded at the apex
3 Presumably in response to the presence of a 'pupal'
stage in the life-cycle, some entomologists refer to the
active juvenile stages of thrips as 'larvae'. However,
this ignores clearly defined structural differences be-
tween insect 'larvae' and 'nymphs' which hold sway in
the present work (see p. 11).
Fig. 47 Tip of the abdomen of a female thrips: (a)
suborder Terebrantia; (b) suborder Tubulifera.
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