WHEAT THRIPS EGGS AND LARVA. 307 



blackish and whitish rings, it is more probable that bis speci- 

 mens were the same which I now have before me from Wiscon- 

 sin. Be this as it may, the communication from Mr. Williams 

 is important, as making us acquainted with an enemy of the 

 wheat crop of which we heretofore have had no definite know- 

 ledge, and which will undoubtedly at times be quite detrimental 

 in the wheat-growing districts of our country. 



Although this species, like many others in this order, occurs 

 upon the flowers of different plants, it is upon wheat, in all pro- 

 bability, that it will be oftenest noticed, and to which it will 

 prove most injurious. It may therefore appropriately be named 

 the wheat Thrips, T. Tritici. 



Attached to the surface of the shrivelled flower-leaves in the 

 quill in which these insects were sent me, I meet with what 

 I doubt not are their egg<t (see figure a, next page,) deposited pro- 

 bably by one of the females after being imprisoned. They are so 

 minute as to be wholly invisible to the naked eye, except when 

 placed upon clean white paper, when they can be merely dis- 

 cerned, appearing like an atom of dark colored dust. Under the 

 magnifier they are discovered to be of a bright red color, like par- 

 ticles of sealing-wax, and of an oval almost globular form; and 

 they are attached to the leaf by a short, thick, crinkled stalk or 

 stem, which is of a dull white color. 



The larvce (fig. b) resemble the perfect insects, except that 

 they are wholly destitute of wings and are smaller and softer, 

 with the several segments of the body more equally and distinct- 

 ly separated from each other by transverse, constricted lines. 

 They are throughout of a bright orange-yellow color, of the 

 same hue as the worms of the Wheat-midge, which worms, how- 

 ever, small as they are, appear like giants when placed by the 

 side of these larva?. 



Two minute blaclc dots upon the anterior end of the head are the eyes. The 

 head is square and but half as broad as the second segment, which is broadest at 

 its base, narrowing forward to its apex, where it is of the same width as the head. 

 The third and fourth segments are slightly longer and wider than the second, and 

 much longer than the following ones, which are about equal to each other, the 

 apical one being narrowed, of a tubular conic form and two-jointed. The body is 

 quite convex above and beneath. The legs and antenna? are much like those of the 

 perfect insects, except that they are shorter. The two minute joints at the end of 

 £he antennae ,(see figure / ) can commonly be pereeived in the larva state of these 

 organs. 



