246 BRITISH GUIANA TIPULIDAE 



tioii of Sc2, that is at the tip of Sci and not retracted backward 

 toward the wing-base to a greater or less degree. It seems to be 

 most nearly allied to this genus, however, and it is better to refer it 

 here than to create a new group on insufficient material. 



GenuH SIGMATOMERA Osten Sacken 

 18G9. Sujmalomcra Osten Sacken, Mon. Dipt. N. Am., iv, 137, 138. 



Sigmatomera apicalis sp. n. 



Color yellowish; wings yellow banded and tipped with brown. 



Male. — Length, 13.6 mm. ; wing, 12.8 mm. ; antennae, 6 mm. 



Male: Rostrum short, dark brown, the palpi yellowish brown. Antennae 

 dark brownish black, the second segment slightly paler basally, segments 

 three to nine (the first seven flagellar) with the extreme apex pale, almost 

 whitish ; the first four segments of the flagellum show the deep constrictions 

 that give to the segments the S-shaped appearance, but beyond these 

 first four this appearance is gradually lost and the apical segments are 

 elongated and but little constricted. Eyes large, nearly approximated 

 above, so that the space on the vertex between them is very narrow and 

 reduced; head blackish in front, yellowish red behind. 



Thoracic dorsum rather shining reddish yellow, without apparent darker 

 .stripes. Pleura yellowish brown. Halteres rather long, dull yellow. Legs 

 reddish yellow, the femora rather broadly tipped with darker; tibiae light 

 brown tipped with darker; tarsi dark brown. Wings rather uniform light 

 yellow, a rather narrow darker band along the cord, an interrupted basal 

 band and the apex of the wings lighter brown. Venation: (see pi. Ill, 

 fig. 9) cell 1st Ma closed. 



Abdomen brownish yellow, darker toward the tip, the hypopygium and 

 segment eight dark brown. 



Habitat. — Bartica, February 21, 1913. 



Holotype, cf, Bartica, February 21, 1913. 



In its closed cell 1st M^ this agrees most closely with the type of 

 the genus which has only a narrow brown seam to the cord. The 

 color pattern of the wing agrees much more closely with amazonica 

 Westwood, but here the thorax is blackish and cell 1st M2 is open 

 by the lack of the outer deflection of M3. 



A Key to the Species of Sigmatomera Osten Sacken 



1. Cell Isl M2 open; thorax black [apical band on the wings narrow, barely 

 including the outer end of cell 2nd R\; middle crossband broad : 

 bapal band suffusing most of the anal lobe]. (Brazil) 



amazonicd Westwood'''' 

 Cell 1st Ml closed; thorax yellowish 2 



'< 1881. amazonica Westwood, Trans. Ent. Soc. Lond.. 1881, 366, pi. 

 17,'fig. 3. 



