CHAPTER XV 

 ORDER THYSANOPTERA * 



The Thrips 



The members of this order are minute insects with wings or wingless. 

 The winged species have jour wings; these are similar in form, long, narrow, 

 membranous, not plaited, with but few or with no veins, and not commonly 

 with cross-veins; they are fringed with long hairs, and in some species are 

 armed with spines along the veins or along the lines from which veins have 

 disappeared. The mouth-parts are formed for piercing and sucking. The 

 tarsi are usually two- jointed and are bladder-like at the tip. The metamor- 

 phosis is incomplete, but deviates from the usual type. 



The species of thrips occurring in our fauna are of small size, rarely 

 more than ^ to \ of an inch in length. They can be obtained easily, 

 however, from various flowers, especially those of the daisy and clover. 

 Ordinarily it is only necessary to pull apart one of these flowers to find 



Fig. 139. — Thrips. 



Fig. 140. ■ 

 original. 



Fore wing of Mlothrips nasturlii. (After Jones.) The lettering is 



several thrips. They are in many cases very active insects, leaping or 

 taking flight with great agility. 



The body is long (Fig. 139). The antennas are filiform or moniliform 

 and consist of from six to nine segments; they are always longer than 

 the head and may be two or three times as long. The compound eyes 

 are large, with conspicuous facets, which are circular, oval, or reniform 

 in outline. Three ocelli are usually present in the winged forms. The 

 mouth-parts are fitted for piercing and sucking; they are in the form 

 of a cone which encloses the piercing organs. The cone is composed of 

 the clypeus, labrum, maxillary sclerites, and labium. The piercing organs 

 consist of the left mandible (the right mandible is vestigial) and the 

 two maxillse. The mouth-parts of the Thysanoptera bear a striking 

 resemblance to those of the Hemiptera. The wings are laid horizontally 

 on the back when not in use; they are very narrow, but are fringed with 

 long hairs (Fig. 140). The fringing of the wings suggested the name 

 Thysanoptera. 



* ThysanSptera: thysanos (dvaavoi), fringe; pier on (irrepov), a wing. 



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