2 74 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. reticiilatus 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, tj. S. Dep. Agric. 

 Bur. Ent. Techn. Ser. 12. III. 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 i mm. 



Head (fig. 2 a) wider than long (4:3); sides of tlie head almost straight, 

 parallel; anterior margin slightly elevated in the middle; back of the head 

 transversely wrinkled, the wrmkles 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: 



segment I 



length __... 2,33 



width (dorsal aspect) 3,67 



» (lateral » ) 2 



Segment I distinctly depressed dorsiventrally, II somewhat compressed laterally ; 

 III and IV constricted at the top; V joined by moderately broad surface to 

 the base of VI. Segments I, II, 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 

 promment. At the side of this stands another somewhat longer and stouter spine. 



