184 PROCEEDINGS OF THE NATIONAL MUSEUM. 



various times that I have included a reference to it under this species, 

 thouo-h its correctness is questionable. 



Dr. Packard found that this insect has been observed attacking onions 

 for fifteen j^ears previously, but the damage in 1872 was unusually 

 severe in Essex County, Massachusetts, amounting that year to at 

 least one-tenth of the crop, and having a money value in that one 

 county of at least $10,000. 



In 18S9, Dr. Thaxter found the Onion Thrips generally distributed 

 and ver}' injurious to onions in Connecticut, the injury produced ))eing 

 i<nownas "White Blast." 



The next report of very serious injury was made by Prof. C. P. 

 Gillette from Colorado, where for several seasons it had been noticed 

 as very abundant and doing considerable harm. It has also been found 

 a serious pest all through the Middle States and in several of the 

 Atlantic coast States as well as on the Pacific coast. This shows its 

 very wide general distribution, and since its attacks seem to be most 

 severe upon onions and cabbages — two important garden crops — it 

 must be considered as, perhaps, the most injurious species of the order. 



THRIPS PERPLEXUS (Beach). 



Plate VI, figs. 66-68. 



Sericothrlps? perpZea,-a Beach, Proc. Iowa Acad. Sciences, 1895, III, (1896), pp. 

 216-218. 



Female. — Length 0.935 mm. (0.80 to 1.0 mm.); width of mesotho- 

 rax 0.197 mm. (O.IS to 0.21 mm.). General color: head brown and 

 thorax reddish orange-brown, very much darker than the pale yellow 

 or gray-brown abdomen; body slender. 



Head very large, somewhat pentagonal, approximate!}^ as long as 

 broad or but slightly shorter, almost as large as prothorax, within 

 which it is slightly withdrawn; cheeks nearl}^ straight and parallel; 

 anterior margin broadly elevated; without special prominences between 

 bases of antenna?; occiput transversely wrinkled; without conspicuous 

 spines. Eyes black, not protruding, together occupying about one- 

 half the width of the head, margins lighter colored; ocelli conspicuous, 

 large and well separated, placed far forward, all three being in front 

 of the middle of the eyes, reddish yellow with maroon inward margins; \. 

 ocellar bristles moderately long. Maxillary palpi three segmented, j 

 Antennae fully twice as long as head, subapproximate; relative lengths j 

 of segments: 



12 3 4 5 6 7 

 6.6 7.6 10.4 12 8.8 13 6.1 



Segment one broader than two which is intermediate in thickness I 

 between one and three; three and four thickest at about their middle • 

 then tapering gradually to the ends; seven bluntly conical. Spines 



