274 OLOF AHLBERG 
This species differs in many important details from the other species of 
this genus. It seems, however, to be nearest related to S. ret7culatus Moulton, 
as far as I can judge from the author’s description and figures. (A contribu- 
tion to our knowledge of the Thysanoptera of California, U. S. Dep. Agric. 
Bur. Ent. Techn. Ser. 12. Il. Washington 1907.) 
Physothrips Skottsbergi n. sp. — Fig. 2. 
Female: Body of the typical shape of this genus; wings well developed; 
colour almost uniformly brown; length 1 mm. 
Head (fig. 2a) wider than long (4:3); sides of the head almost straight, 
parallel; anterior margin slightly elevated in the middle; back of the head 
transversely wrinkled, the wrinkles appearing on the sides as small dents; 
bristles small and inconspicuous, except the ocellar ones, which stand obliquely 
inside and in front of each posterior ocellus. Eyes rounded, not protruding. 
Ocelli large and distinct. 
Mouth-cone moderately pointed; its sides almost straight. Maxillary palpi 
3-segmented; segments I and III nearly equally long, II */s shorter. Labial 
palpi as long as the terminal segment of the maxillary palpi, but more slender. 
Antennae (figs. 2 b and c) 8-segmented, twice as long as the head; relative 
measurements of segments: ) 
SEOMIe Nene es eee ee I] II IV V VI VIF Svan 
len ety ee mote, 2,33 4,33 5 4,67 3,9 5,67 I 1,67 
width (dorsal aspect) 3,67 355 247 2,33 2,2 2.2 0,9 0,67 
» (lateral es a 3,67 Bie a Be oh snes ras 
Segment I distinctly depressed dorsiventrally, Il somewhat compressed laterally; 
III and IV constricted at the top; V joined by moderately broad surface to 
the base of VI. Segments I, I], V and VI brown, III brownish yellow, IV, 
VII and VIII a little darker than III, but lighter than the other segments. 
Prothorax (fig. 2 a) as long as the head, but wider (length : width = 3:5), 
distinctly wider posteriorly; pronotum like the head transversely wrinkled; each 
posterior angle bears a pair of short and stout bristles, standing somewhat 
apart, the interior spine being distinctly shorter than the exterior one. Along 
the posterior edge stands on each side a row of 4 small and inconspicuous 
bristles, the interior of which is longer than the other ones. 
Pterothorax as long as wide, not quite twice as wide as the head. Meso- 
scutum distinctly transversely wrinkled Metascutum has anteriorly on each 
side near the median line a long and stout bristle, and at the side of this a 
weaker one. 
Anterior wings almost uniformly brownish yellow, with a slightly lighter 
spot at the base. Longitudinal veins with a complete row of spines. Posterior 
wings clear. 
Anterior legs stouter than the other ones, unarmed, with distinctly thickened 
femora. The comb at the interior side of the posterior tibiae consists of 8 
short spines, the terminal one of which, standing externally at top, is stout and 
prominent. At the side of this stands another somewhat longer and stouter spine. 
