26 CHARLES P. ALEXANDER 
flection of A4,5; cell 1s¢ JZ, closed; basal deflection of Cm, at or very close to 
the fork of J. 
Abdomen dark brown, the valves of the ovipositor redd.sh horncolor. 
Ovipositor with the tergal valves straight, rather long and slender; sternal 
valves but little shorter than the tergal valves. 
Flabitat, — Endemic in the Juan Fernandez group. 
Holotype, ¢, Masatierra, December. — Paratopotypes, 2 ?’s, January and 
July. — Paratypes, 3 ¢’s, Masafuera, February, March. 
Type in the Riksmuseum in Stockholm. 
This dark-winged Décranomyza with its dark reddish praescutum does not 
agree with any of the numerous species of the genus described from the Chilian 
mainland. It is dedicated to the memory of ALEXANDER SELKIRK — »Ro- 
binson Crusoe» —, who spent the years between 1704 and 1709 on the island 
of Masatierra. 
Subfamily Tipulinae 
Tribe Tipulini 
Genus Tipula Linneus 
Tipula biickstr6émi, sp. n. 
Antennae bicolorous; mesonotal praescutum reddish brown with two 
narrow, dull yellow stripes, one on either side of the capillary median brown 
vitta; halteres dark brown, the base of the stem yellowish; femora with a 
narrow dark brown ring before the tip; wings uniformly brownish gray, stigma 
dark brown. 
Female. — Length about 22 mm.; wing, 18 mm. 
Frontal prolongation of the head brownish yellow; nasus distinct; palpi 
dark brown. Antennae with the four basal segments light yellow, the inter- 
mediate flagellar segments indistinctly bicolorous, the apical flagellar segments 
more uniformly brown; verticils moderately elongated. Head grayish brown; 
a capillary dark brown median line extends the whole length of the vertex 
onto the vertical tubercle. 
Mesonotal praescutum reddish brown with faint dull yellow stripes, the 
most distinct being one on either side of a capillary dark brown median vitta; 
the brown lateral stripes are indistinct, separated from the median stripe by a 
very faint yellowish border; scutum brown, sparsely gray pruinose; scutellum 
and postnotum pale brown, the latter sparsely gray pruinose. Pleura yellowish, 
with a very sparse white bloom. MHalteres dark brown, the base of the stem 
abruptly yellowish. Legs with the coxae yellowish, with a sparse white bloom; 
trochanters dull yellow; femora dull yellow with a rather narrow, dark brown, 
annulus immediately before the tip: tibiae yellowish brown, the tips narrowly 
and indistinctly darkened; tarsi pale brown, becoming darker on the terminal 
segments; legs long and slender, the tibiae a little longer than the metatarsi. 
Wings with a strong brownish gray suffusion, the costal cell more yellowish, 
