Thrips obviously differ morphologically and in their life cycle from other insect orders
Name: The name of the order Thysanoptera is formed out of the ancient Greek words θύσανος (thysanos = fringe) and πτερόν (pteron =wing), for the insects’ fringed wings. Other common names include thrips, thunderflies, thunderbugs, storm flies, thunderblights, storm bugs, corn flies, corn lice and freckle bugs; Pysopoda or bladder-feet are obsolete terms.
The generic and English name thrips is a direct transliteration of the ancient Greek θρίψ (ips, meaning: woodworm). It was created by Linné and refers to species living under the bark of deadwood and to their thigmotactic behaviour.
Like some other animal names (such as sheep, fish, deer, or moose), the word thrips is both the singular and plural form. So there may be many thrips or just a single thrips.
The old name bladder-foot (physopod or Physopoda) derived from the enlarged eversible adhesive pads (arolia) on the praetarsi of the thrips’ legs. These structures have originally been misinterpreted as small bladders.
During mass flights the occurrence of some thrips species becomes spectacular when myriads of individuals rise into the air, resembling dark clouds. These phenomena are initiated by hot weather conditions and appear mostly on midsummer days with a high probability for thunderstorms. Due to this swarm behaviour of some grass living taxa (Limothrips), the Thysanoptera in general earned the name thunderflies, thunderbugs or thunderblights, most likely long before they have been recognized as an own insect order in 1744.
Body size: In general, thrips are about 1 to 2 mm long and appear slender and elongated. Despite of their small body size they can be distinguished from other small insects by their typical worm-like crawling movement. Giant forms, up to a body length of about 15mm, are to be found in tropical regions only.
Thrips differ from other insects in the asymmetry of their piercing and sucking mouthparts. Labrum, stipes and labium form a backward directed mouth cone containing three stylets: the left mandible is an unpaired, elongate but solid stylet, whereas both laciniae are developed as slender maxillary stylets. Many species are able to retract these stylets deep in the head capsule. Longitudinally, they are linked together by a tongue and groove system to produce a feeding tube with a sub-apical aperture and one central channel that also functions to inject salivary secretions. The right mandible does not develop beyond the embryo.
The life history of thrips is unlike that of other insects. Following two actively feeding larval stages, there are two (three among Phlaeothripidae) non-feeding pupal stages before the adult is produced. The order Thysanoptera is considered part of the Hemipteroid complex, the Paraneoptera. But the life history distinguishes the group, and it is best regarded as an exopterygote that has independently adopted holometaboly.