112 Proceedings of the Biological Society of Washington. 



Heterothrips lyoniae sp. nov. 

 (PI. Ill, Fig. 2.) 



Female (macropterous). — Length about ].l mm. Color dark blackish 

 brown with tarsi, distal ends of tibipe, and third antennal segment pale 

 grayish yellow ; fore wings dark brownish gray except for a white, trans- 

 verse, subbasal band. 



Head about 1.7 times as wide as median dorsal length, distinctly shorter 

 than prothorax, widest behind eyes, thence narrowing abruptly to ej^es 

 and tapering slightly to base; surface with a few minute spines, impressed 

 and transversely rugose in front of anterior ocellus, smooth between 

 ocelli, and with four or five anastomozing striae on occiput ; frontal costa 

 with deep U-shaped emargination ; ocellar area not delimited bychitinous 

 lines. Eyes setose, two-thirds as long as head, as wide as their dorsal 

 interval. Ocelli of posterior pair twice the diameter of anterior ocellus, 

 a little less than half as wide as their interval. Antennae about three 

 times as long as head; segment 3 subconical, three times as long as wide, 

 with deep incisions at basal fifth and basal two-fifths ; 4 more than half 

 as wide as long, roundly tapering to base; 5-8 more or less barrel-shaped, 

 with sense cones; 9 about three times as long as wide; segments one and 

 2 nearly concolorous with head ; 3 yellow, tipped with gray; 4 blackish 

 brown, with an apical band of yellow and with middle of basal half 

 paler; 5-9 blackish brown. 



Prothorax about one and one-half times as long as head and about 1.5 

 times as wide as long, sides and posterior margin rounded, anterior 

 margin straight; notum with a few short spines, its surface free from 

 sculpture except for two or three anastomozing striae near posterior 

 margin. Wings of fore pair half as wide at middle as near base, the 

 greatest subbasal width (exclusive of scale) about one-eighth the length 

 of the wing; costal margin, anterior vein, and posterior vein with about 

 28, 25, and 18 short, stout spines, respectively, these being closer together 

 toward base of wing. 



Abdomen stout; pubescence very sparse, disposed on strong, anasto- 

 mozing lines (much as in H. flavicornis, figured in Ins. Insc. Menstr. , 

 Vol. Ill, 1915, PI. I, Fig. 3); posterior margins of abdominal tergites 

 1-7 fringed at sides with contiguous, chitinous scales or plates, whose 

 apical margins are evenly produced in long slender spines, giving a 

 comb-like appearance ; median line of tergite of segment 1 unarmed ; 

 segments 2-5 with a few slender spines at middle of posterior margin ; 

 6 and 7 with a regular fringe of stronger spines between the lateral plates ; 

 sternites 2-6 fringed across their entire posterior margins with chitinous 

 plates, which are divided apically into about ten slender spines. 



Measurements of holotype: Length 1.07 mm. ; head, length 0.099 mm., 

 width 0.149 mm.; prothorax, length 0.147 mm., width 0.223 mm.; 

 pterothorax, width 0.284 mm. ; fore wing, length 0.756 mm., width at 

 base 0.090 mm., at middle 0.045 mm.; abdomen, width 0.396 mm. 

 Antennal segments: 123456789 



Length (m) 24 39 81 46 28 28 21 17 23 



Width (m) 30 27 27 27 20 16 12 10 7 



Total length of antenna, 0.307 mm. 



