42 The Crasjjedosomatidas of North America. 



At the same time the differences fire so great that to unite the 

 genera as several authors have clone seems unwarranted. In ad- 

 dition to the above diagnosis, the following description applies 

 to the species noticed in this paper : — 



Body fusiform, broadest in the anterior portion, narrowed very abruptly 

 cephalad, very gradually caudad; in cross-section circular, slightly compressed 

 dorso-ventrallj^ in front of the middle, slightly compressed laterally caudad. 

 CarintE very small, placed near the middle line of side. 



Vertex prominent, nearly smooth, shining. 



Clypeus sparsely hirsute with short and long hairs ; a prominent transverse 

 supralabral ridge, above which are a few more or less evident fine transverse 

 wrinkles. Along the lateral margins a deep, somewhat oblique furrow curv- 

 ing mesad below, above the transverse ridge. 



Eyes in a triangular patch, arranged in several transverse rows; as in other 

 genera there is usually one ocellus on the lateral margin above the upper row, 

 with which it is usually counted. 



Antennae moderately hirsute, the distal joints more hirsute than the basal. 

 Approximate proportions of lengths of joints beginning with the seventh, 

 3:3:7:5.5: 10:5:2. 



First segment, viewed from above, pointed reniform; surface smooth, ex- 

 cepting three very small light-colored protuberances on each side ; the lateral 

 located at the extreme corner of the superior surface of the segment; the second 

 a short distance mesad and cephalad from the first; the third nearer to the 

 median line than to the second. Tlie bristles measure as much as .15 mm. in 

 length. 



Subsequent segments with the lateral carinse more pronounced for six or 

 seven segments, whence they decrease in size. On the anterior segments the 

 lateral bristle-bearing protuberance is close to the posterior margin ; on suc- 

 ceeding segments it is not so close, until the antepenultimate is reached. As 

 the carinse decrease the bristles of the lateral protubei'ances increase, poster- 

 iorly ; they are directed horizontally and appressed to the side of the body. 

 The middle pair of protuberances approach the median line on posterior seg- 

 ments, and the six bristles are more and more nearly arranged in a straight 

 transverse row. A fine median ridge placed in a furrow runs from the first to 

 the last segment. 



Anal segment without median furrow or ridge; broadly truncate or slightlj'' 

 emarginate posteriorly and deeply sinuate on the sides; with eight bristles, of 

 which two are located on the anterior portion, near the median line; the others 

 are directed more or less horizontally from the posterior margin. The median 

 pair have thickened conical bases nearly as long as the slender bristles rising 

 from them. The other bristles are located at the corners of the truncation 

 and the iipper part of the lateral sinuation. Posterior margin very thick and 

 slightly gTOOved posteriorly. 



Anal valves slightly exceeding the anal segment, not strongly convex, more 

 prominent above the middle, and angulate, the margins scarcely raised; above 

 on each side with three bristles at equal distances from each other. 



