676 FAUNA HAWAII EN SIS 



account of the usual bristles being obsolete, thus approaching the condition seen in the 

 Urothripidae ; whilst Dolcrothinps possesses a character common to all the species in 

 the fore-coxa, which, instead of being furnished with one prominent bristle is very 

 strongly spinose. In all the species of this latter genus too, we notice that the mid- 

 lateral, posterior-marginal pairs of bristles and the pair at posterior angles of prothorax 

 are more or less well developed, whilst the anterior-marginal and pairs at anterior angles 

 are either poorly developed or obsolete. 



In tabulating the species oi Dolerothrips we have found characters connected with 

 the bristles of decided importance ; thus in D. perkinsi the lateral bristles of the eighth 

 abdominal segment have been considerably reduced, in D. interuiedms all the bristles 

 are much shorter than in other species, excepting the extreme and interesting form 

 ■ lanaiensis wherein all the bristles are very weak and greatly reduced, approaching the 

 condition seen in Dernwthrips. 



2. Systematic Accojcnt. 



Order THYSANOPTERA. 



Insects of the order Thysanoptera possess certain features which at once separate 

 them from all orders ; principally the semi-mandibulate and semi-suctorial mouth ; the 

 fringed wings and the bi-articulated foot, which latter is furnished with a retractile 

 bladder-like organ, a characteristic embodied in the ordinal name Physapoda, a name 

 adopted by many entomologists. 



It is beyond the scope of the present contribution to go into the details of the 

 anatomy, nor is it necessary when one can consult the excellent works of Haliday, 

 Jordan, Uzel and Hinds'. But recently we have had the pleasure of describing a new 

 type of Thysanoptera, Urothrips paradoxus Bagnall, differing in so many points from 

 all other forms as to modify considerably our ideas as to the relationships and 

 phylogeny of the thrips, and also their systematic arrangement ; therefore, whilst 

 adopting Haliday's very convenient classification herein, we cannot pass unnoticed an 

 insect that will without doubt be an important factor in the future classification of the 

 order". 



Urothrips, whilst undoubtedly Tubuliferan in its affinities, differs from all known 

 forms in both divisions of the Thysanoptera by the possession of single-jointed 

 maxillary and labial palpi ; of eleven pairs of well-developed stigmata instead of four pairs ; 



' Haliday, Entomological Magazine, ni. pp. 439 — 451, 1837, and in Walker's Homopterous Insects, 

 Brit. Mus. pt. IV. pp. 1094 — 1118, 1852; Hinds, Proc. U.S. Nat. Museum, xxvi. pp. 79 — 242, 1902; Jordan, 

 Zeitschrift f. wissensch. Zoologie, xlvu. pp. 541 — 620, 1888; Uzel, Monographie der Ordnung Thysanoptera, 

 1895. 



Bagnall, Annales Musei Nationalis Hungarici, vii. pp. 125 — 136, pi. iii. 1909. 



