61 



ON TWO SPECIES OF PHYSOTHRIPS (THYSANOPTERA) INJURIOUS 



TO TEA IN INDIA. 



By Richard S. Bagnall, F.L.S. 



The two species of thrips described in the following pages have been found on 

 tea in sufficient numbers as to be regarded as pests, and they should therefore be made 

 known to economic biologists. A member of the sub-order Tubulifera (Haplothrips 

 sp.) was also found both by Prof. Maxwell Lefroy and Mr. Andrews on tea, but it 

 seems to occur also on other plants ; I have not yet had the opportunity of studying 

 it.* 



P. lefroyi is a strongly characterised species both in structure and coloration ; 

 whilst P. setiventris, when both sexes are taken, should be easily recognised by the 

 black " tail " of the $. The former species may ultimately be removed from the 

 genus Physothrips, with advantage. 



Physothrips setiventris, sp. nov. (fig. 1). 



$. Length about 1"2 mm. 



Head light grey-brown ; prothorax and pterothorax yellowish, lightly shaded 

 with grey-brown to brown ; abdomen chestnut-brown. Antennal joints 1 and 2 

 grey-brown, as dark as or slightly darker than head ; 3 pale yellow ; 4 brown, with 

 extremities clear or yellowish ; 5, 6 and style chestnut-brown, concolorous with abdo- 

 men. Legs pale yellow ; femora, chiefly along outer margins, scarcely noticeably 

 tinged with grey or grey-brown. Pore wing with basal fourth (or thereabouts) 

 clear, thence brown to the apical eighth (which is also clear), this brown area being 

 somewhat fighter about the middle and giving a banded appearance ; setae brown, 

 cilia smoky. 



Head about 0"7 as long as wide ; cheeks subparallel, almost imperceptibly arched ; 

 dorsal surface irregularly transversely striate posteriorly. Eyes in greatest dorsal 

 length occupying about 0'6 of the total length of head, moderately coarsely facetted, 

 pilose ; space between eyes about the width of one of them ; ocelli set well back, 

 posterior pair on a line drawn across the basal fifth of eyes, with a pair of well- 

 developed interocellar bristles between them. Mouth-cone reaching well across 

 presternum ; maxillary palpi long, 3-segmented the middle joint being the shortest. 

 Antennae set below the vertex, sub-approximate, 2 "3 times as long as the head ; 

 all usual setae long, prominent ; segments minutely setose in more or less ring-form ; 

 relative lengths of segments approximately as follows : — 16 : 28 : 40 : 36 : 24 : 

 29 : 5 : 10 ; form normal, segment 6 short and stouter than is usual, being approxi- 

 mately equal in length to 2 ; forked sense-trichomes on 3 and 4 with the arms widely 

 branching (fig. 1 c). 



Pronotum subquadrate, about 1"2 times as long as the head and T25 times as 

 broad as long ; posteriorly margined ; surface sparingly setose. The pair of setae 

 at posterior angles rather stout, subequal in length and about - 45 the length of the 

 prothorax. Pterothorax normal, only very slightly longer than broad. Legs normal, 

 sparingly setose ; hind tibia with a series of stout setae at apex within, and the 



* Haplothrips tenuipennis, Bagn. (Ann. Mag. N H. (9) i, March, 1918). 



