132 INSECUTOR INSCITLE MENSTRUUS 



appcirent from the descriptions is a pair of dark spots on the frons near 

 the ocellcir triangle, present in monochata and absent in trilineatus. 

 With the otherwise close agreement, too much VcJue can not be con- 

 ceded to this difference. 



Trigonometopus Macquart. 



As here restricted, this genus includes those species which have the 

 face flattened cmd strongly receding, the mouth on the ventral aspect, the 

 clypeus not produced toward the antennae ; two pairs of fronto-orbital 

 bristles, postvertical bristles present. The following table will serve to 

 separate the species of the Oriental region. 



1. Mesonotum pale, with (our brown longitudinal stripes .... 2 

 Mesonotum pale, with a pair of broad lateral stripes . . setosus, n. sp. 



2. Wings with brown costal shade ........ 3 



Wings yellowish, without costal shade .... brevicornis Meijere 



3. Costal brown shade beginning at base of wing . . . bakeri Bezzi 

 Costal shade beginning at tip of auxiliary vein . . . albiseta Bezzi 



Trigonometopus setosus, new species. 



Female : Head rather short, the face flat and receding, the clypeus 

 forming a prominent rim around the ventrally situated mouth. Eyes 

 rounded, broadest anteriorly. Frons broad, slightly wider than one eye, 

 nearly parallel-sided, narrowed and only slightly produced beyond the 

 eyes ; two pairs of very large fronto-orbital bristles, postverticals long and 

 cruciate. Antennas prominent, blackish, a whitish spot on inner side 

 involving second joint and base of third ; third joint rounded, compressed, 

 pubescent ; arista long, black, setose. Frons pale yellowish with whitish 

 pruinosity, the ocellar callosity black, a pair of large triangular spots ante- 

 riorly from eyes to antenna ; a pair of large black spots above behind 

 eyes ; face and entire lower part of head pale yellowish ; palpi slender, 

 ferruginous yellow at tip, wath a few black setae. Mesonotum with a 

 broad yellowish, slightly pruinose, median stripe and browmish black lat- 

 eral stripes, these latter extending to dorsocentrals and occupying almost 

 one-third the width of thorax. Scutellum concolorous with median stripe 

 of mesonotum, the sides from base to apical third blaclcish in continuation 

 of lateral mesonotal stripes. Pleurae pale yellowish. Three pairs of very 

 long dorsocentral and two pairs of scutellar bristles. Bristles and hairs of 

 head and thorax black, the macrochaetoe very long and coarse. Abdo- 

 men dorsally blackish, with trace of a median reddish brown stripe on 



