THYSANOPTERA 679 



Prothorax transverse, only one-half as long as broad ; setae obsolete excepting the 

 posterior-marginal pair which are short and weak. Surface roughly sculptured with the 

 disc irregularly depressed. Pterothorax as wide as the width across fore-coxae, about 

 three-quarters as long as broad ; fore-part of mesothorax scabrous, dorsal surface 

 squamose and metathorax reticulated. Legs somewhat short, all femora slighdy 

 swollen ; fore- and intermediate-coxae strongly projecting , fore-coxa scabrous, without 

 any prominent bristle, and fore-tarsus unarmed. Sculpture of all femora the same 

 as that of the head, all tibiae less markedly scabrous and more strongly and regularly 

 setose. 



Abdomen oblong-ovate, one and two-thirds as broad as the pterothorax, widening 

 from base to the fourth segment and narrowing from the sixth segment to base of tube. 

 Surface shagreened, very sparsely, irregularly and minutely setose ; the second segment, 

 a good part of the third and the sides of the succeeding segments having a squamose 

 appearance as in the pterothorax. Tube about two-thirds the length of the head and 

 about two and one-half times as long as broad at base, narrowing from apical third to 

 tip, where it is only one-half as broad as at base. Surface of tube smoother and more 

 shining than the rest of the abdomen, and showing signs of reticulate sculpture. 

 Terminal hairs a little more than one-half the length of the tube ; all abdominal hairs 

 very weak and minute. 



J. Length r5 mm. There is a single specimen of what is apparently the male 

 of Dernwthrips hawaiiensis. It is only about three-quarters the average length of the 

 female, and is much narrower in comparison to the length, having the abdomen linear 

 and only about one and one-quarter times as broad as the pterothorax. The fore-leg is 

 stouter, and the tarsus is armed with a short tooth. The tube is comparatively longer 

 and narrower. 



Forma macroptcra. 



%. Length 2-1 to 2-5 mm. The winged form is on an average distinctly larger 

 than the wingless specimens. The pterothorax is developed, whilst the abdomen 

 is furnished with wing-retaining spines. The eyes are comparatively larger; the 

 ocelli are present though very small, the posterior pair being on a line drawn through 

 the posterior third of eyes, and near to their inner margins. The wings are long and 

 narrow, reaching the ninth abdominal segment. They are of a smoky colour with 

 a dark vein running for more than one-half the length, this vein being ridged for a little 

 more than half its length from the base. In the specimens examined, all of which 

 come from the island of Oahu, the wings lie so closely to the abdomen and seem 

 so slender in comparison to the heavy body, as to suggest long disuse. 



Hab. Kauai, Oahu, Maui, Hawaii. 



87—2 



