78 Proceedings of the Biological Society of Washington. 



about 1.8 times as wide as long, surface smooth, median line faintly in- 

 dicated; all bristles present, blunt, the anterior marginals shortest, the 

 posterior laterals longest, others subequal to postoculars. Wings of fore 

 pair slender, narrowed at middle, and with seven (rarely, six) interlocated 

 hairs on posterior margin near apex. Fore tarsus with a minute tooth. 



Abdomen about equal in width to pterothorax. Tube 0.55 as long as 

 head, twice as long as basal width, and less than twice as wide at base as 

 at apex. Bristles largely blunt; terminal bristles shorter than tube. 



Measurements of holotype ( 9 ) : Length 1.39 mm. ; head, length 0.209 mm., 

 greatest width 0.166 mm., width at base 0.141 mm.; eyes, length 0.080 mm., 

 width 0.045 mm., interval 0.066mm.; postocular bristles, length 0.030 mm.; 

 prothorax, length 0.138 mm., width (inclusive of coxae) 0.257 mm.; ptero- 

 thorax, length 0.312 mm., width 0.292 mm.; abdomen, greatest width 

 0.286 mm.; tube, length 0.115 mm., width at base 0.057 mm., at apex 

 0.032 mm. 



Antennal segments: 1 

 Length (m) 33 



Width (m) 32 



Total length of antenna, 0.325 mm. 



Male (macropterous) . — Length about 1.3 mm. Color and structure es- 

 sentially as in female, except as follows: Head about 1.34 times as long as 

 wide, 0.89 as wide at base as behind eyes. Eyes 0.35 as long as head and 

 three-fourths as wide as their interval. Prothorax 0.77 as long as head and 

 (inclusive of coxae), 1.7 times as wide as long, median line distinctly in- 

 dicated, black. Fore legs swollen, tarsi with a stout triangular tooth. 



Measurements of allotype (cT): Length 1.26 mm.; head, length 0.209 

 mm., greatest width 0.156 mm., width at base 0.139 mm.; eyes, length 0.074 

 mm., width 0.045 mm., interval 0.062 mm.; postocular bristles, length 

 0.033 mm.; prothorax, length 0.161 mm., width (inclusive of coxae) 0.276 

 mm.; pterothorax, length 0.294 mm., width 0.281 mm.; abdomen, greatest 

 width 0.276 mm.; tube, length 0.114 mm., width at base 0.056 mm., at 

 apex 0.031 mm. 



Antennal segments : 1 2 3 4 5 6 

 Length (/x) 31 42 49 50 44 40 



Width (m) 32 26 23 28 24 22 



Total length of antenna, 0.319 mm. 



Described from three females and one male taken by sweeping grass, at 

 Brooklyn, New South Wales, Nov. 7-18, 1914, by A. A. Girault. 



Easily known from the other Australian species of the genus by the 

 long third antennal segment which has no sense cone on its inner surface, 

 and by the antennal coloration. 



Zygothrips pallescens, sp. nov. 



Female (macropterous). — Length about 1.5 mm. Color brownish yellow, 

 with metathorax, first abdominal segment, all tarsi, apical half of tibiae, and 

 antennal segments 3-6, pale yellow; tube dark brown, paler apically. 



