Mr. R. S. Bagnall on neio Thijsanoptera. 397 



Bactridothrips serratlcornis^ sp. n. 



Karny has recently diagnosed the genus Bactridothrips for 

 a Malayan insect, the male differing from that sex m the 

 genus Bactrothrips in the longer processes of the sixth abdo- 

 minal segment and the armature of segments 7 and b. 



A single S example from Ceylon was recently sent me by 

 Mr. Green which would seem to differ from B. idoloniorphus, 

 Karny, in several particulars. 



($ . — Length about 7'0 mm. 



Head 2*5 times as long as broad (as against 2*3 in idolo- 

 murphus) ; antennae very slender, nearly three times as long 

 as the head, with the joints 6 and 7 relatively longer than in 

 idolomorpJivs, the relative lengths of joints 3-8 being approxi- 

 mately 69 : 50 : 43 : oO : 13 : 11, as compared witli 68 : 48 : 

 42 : 27 : 10 : ?. 



The tibiae are golden-yellow in colour, the fore-tibije being- 

 shaded with brown in the basal two-thirds and the inter- 

 mediate and hind pairs are dark brown in the basal half and 

 basal two-fifths (or thereabouts) resj)ectively. All tarsi 

 similarly yellow, with the ends (or second joints) dark brown. 



The horns of the sixth abdominal segment are much 

 shorter than in idolomorphus (a line diawn across their tips 

 would only a])proximate the base of the teeth of the seventh 

 segment), whilst the inner margins are noticeably and irregu- 

 larly serrate in the basal three-fourths or thereabouts. The 

 teeth of the eighth abdominal segment are very much stronger 

 and stouter than those on the seventh, wliilst the sides at 

 middle are inclined to be tuberculate. 



The tube is approximately twice as long as the head and 

 8'0 times as long as broad at base ; the surface is strongly 

 setose excepting in the distal fifth^ the basal half only being- 

 setose in Karny's species. 



The legs are not so long as shown in idolomorphus, and 

 upon careful measurement the intermediate and hind-tibiai 

 (without tarsi) measure O'O mm. and 0*77 mm. respectively, 

 as compared with 1*25 mm. and 0'95 mm. 



Tyi:)e. In Coll. Bagnall. 



Ilah. Ceylon, Pundaluoya ; 1 ^ only {E. E. Green). 



