NO. 1310. NORTH AMERICAN THYSANOPTERA— HINDS. 183 



tluin second; .subpyrifonn, united to second 1>y nuiTow "neck," rather 

 closel}' ringed. Fourth, about as lono- as proximal three together, 

 chib-shaped, ringed as in stage 1. Antenna' bearing seta? much more 

 numerous on fourth joint. Tarsi without the pronounced claw-like 

 structures of the tirst stage. In other respects essentially as in pre- 

 ceding stage. 



Xijiiiph {ahoiit tico d(fyj^ old). — Length about 0.7 mm.; width of 

 niesothorax about 0.15 mm.; color yellowish, varying to almost color- 

 less; eyes reddish. Pu])a-skin somewhat separated from the body 

 proper, being particularly noticeable in the caudal end of the abdomen, 

 wing-pads, legs, and antennte. In these two latter the joints are very 

 obscure, the pupa-skin covering them as a sheath. The wing-pads 

 reach to about the eighth abdominal segment. There are numerous 

 seta^ on the bod}', antemue, legs, and wing-pads. On the abdomen 

 they have practically the same position as in the adult larva. The 

 dorsal setje of the last segment in the nymphs are ver}^ stout, almost 

 hook-like, curving cephalad. 



Z//(' 111 dor ij. — Dr. Lindeman's conclusions, quoted by Dr. Lintner, 

 are so different from those which have been reached by workers upon 

 the same species in this country that we are led to suspect that he has 

 confused the early stages of very different species. 



In Massachusetts, using specimens found infesting a cucumber house 

 in January and February, I have found that the ^^^ stage varies from 

 four to seven days. Pupation takes place in seven or eight days and 

 lasts for nearly a week, when the adults emerge and after a few days 

 lay their eggs. The whole life cycle in a greenhouse thus occupies 

 from three to four weeks. 



In Florida Quaintance found that the ^^g stage lasts in summer 

 from three and a half to four days; the larval stage from seven to nine 

 days, during which time the larva molted twice; the nymph stage four 

 days, the total life cycle thus requiring about sixteen days. There 

 appeared to be no distinct broods at any season. 



Ill Ohio Professor Webster has found that this species hibernates 

 in larval, pupal, and adult stages, the tirst i^redominating, being found 

 in matted grass or refuse tops left in the onion fields, and that they 

 safely passed through winters when the temperature fell to —23 to 

 — 2.5 degrees F. 



Keonomie considerations. — Dr. A. S. Packard, in 1872, was the first 

 to record the ravages of the "Onion Thrips," which he called Limo- 

 thrljjs tritici Fitch, believing it to be identical with the "Wheat 

 Thrips." While Dr. Packard's description is unidentifiable, it is suffi 

 cient to show that the insect was not Thrips tritici Fitch, nor did it 

 belong to the genus Limothrijjs. Furthermore, Packard states that 

 the antenna consists of eight segments, which would separate it from 

 TJirips tahaci^ which has only seven. Still the injury recorded is so 

 like that which is known to hav(^ been committed by T/irips tahacl at 



