THE TUBULIFERA. 183 



are able to produce a mischievous impression even 

 upon these coarser organs^ so as at length to injure 

 the plants to which they belong. This is especially 

 the case with some which infest hothouses and 

 cucumber frames^ where the genial atmosphere ap- 

 pears greatly to assist their development; and the 

 occurrence of a species in Tuscany is recorded^ which 

 does considerable damage to the olive-trees in some 

 parts of that country. 



Although by far the greater portion of these curious 

 little insects belongs to the tribe of the Terebrantia, 

 there are a few species, including the gigantic Idolo- 

 thrips already mentioned, which present some im- 

 portant peculiarities of structure, and have been 

 formed into a second tribe. These have the wings 

 (when these organs are present) membranaceous, 

 almost totally destitute of veins, aud laid one upon 

 the other in repose on the back of the insect ; their 

 setiform mandibles project considerably from the 

 mouth, and their maxillary palpi consist only of two 

 joints. The females also are destitute of the valvular 

 ovipositor possessed by those of the preceding tribe, 

 and the abdomen in both sexes terminates in an elon- 

 gated tubular joint, whence the name of Tubulifera. 

 has been given to the tribe. The insects are far less 

 active than their Terebrant relatives, and never leap 

 in the remarkable manner characteristic of the latter. 



The British species of this tril^e all belong to the 

 genus Phloeothrips, so called from their being for the 

 most part found under the bark of dead trees and 

 old rotten stumps, although several of them are also 

 found in flowers. 



