395 



history, witli description of the species, will be found in a i)amphlet 

 entitled Die schiidlichsten Insekten des Tabali in Bessarabieu (Moscow, 

 1888, pp. 51-7G). 



The fact of the occurrence of this species in Europe indicates, in my 

 opinion, that it is not a native of this country, but that it has been 

 imported from Europe, either with tops of green onions or on leaves of 

 cabbage, infested parts of which were either brought ashore or thrown 

 overboard, while the ships having such vegetables on board lay in oar 

 Eastern harbors. From such i^oints of infection, after having secured 

 a foothold, they gradually spread in all directions, following closely the 

 trunk lines of the railroads, until they reached the Pacific Slope. 



The species may be redescribed as follows : 



Thrips tabaci Lindemau. 



Female. — Leugrli of body, 1 to 1.2""''\ Color, palo yellow, the thorax somewhat 

 darker; sides of thorax aud an elongated squarish spot on the meso-noLum more or 

 less distinctly dusky. Abdominal segments marked with a rather broad, darker, or 

 lighter dusky band posteriorly. Eyes brown. Ocelli colorless, their inner margin 

 more or less distinctly orange. Antenna3 and legs iiale dusky, with tip of tarsi some- 

 what darker. Wings faintly yellowish, their fringes and bristles dusky. 



AntenufB 7-joiuted. Joint 1 shortest aud stoutest; the second slightly longer. 

 Joints 3 to 5 are elongate-ovoid and subequal in length ; the sixth is elongate-conical 

 and longer than the others; the stylus is one-jointed. All are provided with a few 

 stout bristles and the third and fourth in addition with two stout, blunt, curved, 

 sensorial spines near the apex. Head about as broad as long, and transversely stri- 

 ated. Eyes hairy. 



Prothorax longer than broad, slightly narrowed in front; its anterior aud pos- 

 terior angles rounded, and provided with two backward-directed diverging spines at 

 eacli posterior augle; surface transversely striated. Spines aud bristles of the 

 abdomen similar to those of Thrips tritici. Legs rather long aud slender, partic- 

 ularlj" the last iiair. Wings densely covered with minute spines, and with stout 

 spines or bristles along the veins and anterior margin, while the hairs of the fringes 

 are slender and wavy. 



Male. — This sex resembles the female in every respect, except that it is much smaller, 

 narrower, and with the end of the body bluntly rounded. Its length is about 0.7'"'". 



Larva: The mature larva is somewhat smaller than the female, and of a ^laler or 

 darker yellow color, often with a greenish tint. Eyes reddish. Ocelli wanting. 

 Legs pale dusky. Antenufe 6-jointed, short and stout. Joint 1 broader than long; 

 the second about twice as loug, stoutest and rounded at the apex. The third is 

 longer than the second, pyriform and with a short but distinct pedicel, orna- 

 mented with, apparently six, rather shallow annulations; the fourth joint is almost 

 as long as 2 and 3 combined, fusiform, and divided by about eight annulations; the 

 fifth is very short, but indistinctly separated from the fourth, aud much shorter 

 than the last. All bear a few slender hairs. The thoracic and abdominal segments 

 are ornamented with from six to eight transverse rows of closely set, minute, fleshy 

 tubercles, while each of the abdominal segments in addition is provided with a lat- 

 eral bristle, which gradually become longer aud moi'e slender toward the end of the 

 body. 



This species resembles in general appearance Thrips .'striata Osb., 

 T. tritici Fitch, and T. occidentalis n. sp., but difters from all of them in 

 the stylus of the antennjTe, which is only 1-jointed. It belongs evi- 

 dently to Walker's " Section 4, Xeogami," and may form a new sub- 

 genus of Thrips. 



