484 Ricltard S. Bagnall — Fossil Insect in Amber. 



obscures the dorsal surface of the abdominal segments 8, 9, and 

 base of 10, so that it is impossible to describe the arrangement of 

 bristles, shown in the figure as springing from segment 9 with 

 absolute accuracy. The angle of the antennae makes it impossible to 

 gauge the relative lengths of segments. 



Order THYSANOPTERA. 



iSub-order TEREBRANTIA. 



Family HETEROTHEIPID^E, Bagnall. 



Genus Stentjkothrips, nov. 



p Head transverse, about as long as prothorax. Antennae 

 nine-jointed, the first four joints stouter than the succeeding five. 



Prothorax transverse, two prominent bristles at each land angle; 

 mid-lateral pair well developed. Pterothorax well developed. Wings 

 long, fore-wing with two longitudinal veins each uniting with the 

 ring-vein near apex; apparently a cross-vein uniting the longitudinal 

 veins near basal third. Costa and both veins set for whole length 

 with setae. 



Abdomen elongate-ovate, with tenth segment abnormally produced, 

 very elongate, cylindrical, open ventrally for entire length, and longer 

 than the length of liead and prothorax togetlier. Segment 9 furnished 

 with long bristles, and 1 with a series of setae before apex. Ovipositor 

 presumably long and straight. 



Type : Stenurothrips succineus, mihi. 



Of living Thysanoptera this form undoubtedly comes near Hetero- 

 thrips, a Neotropical genus, but is strikingly distinguished by the 

 abnormal development of the tenth abdominal segment, the tubiform 

 appearance suggesting a Tubuliferon. 



We have noticed several forms distinguished by a similar develop- 

 ment, notably Panch(etothrips, a' Heliothripid-like form, distinguished 

 by the form of the explanate margins of abdomen and produced 

 pleurites, and tlie tube-like tenth abdominal segment, in which there 

 is exhibited a tendency for the ventral opening to close. In this 

 form the ovipositor is styliform and but poorly developed. In 

 Dinurothrips, Hood, and JIacrurothrips, Yuillet, the tenth segment 

 is also strikingly developed. 



SxENUROTHKirS STTCCINEUS, Sp. UOV. 



Length about 1"8 mm., breadth of mesothorax 0'35 mm., length of 

 tenth abdominal segment about 0"35 mm. 



Head transverse, about 0"75 as long as broad, and as long as or 

 a little longer than the prothorax. Cheeks sub-parallel, dorsal surface 

 near base faintly striate. Eyes large, moderately closely facetted 

 and apparently pilose; greatest dorsal length equal to about 0-75 the 

 total length of head, and space between eyes about 0'4 the greatest 

 breadth across them. Ocelli moderately large, well sepai'ated, 

 posterior ones close to the inner margin of eyes ; a pair of minute 

 interocular setae present. Two pairs of rather long backwardly 

 directed setae on a line behind eyes, practically equidistant, the 



