1911.] NATURAL SCIENCES OF PHILADELPHIA. 381 



may be found on either the ventral or dorsal surface in two different 

 legs as organ No. 2 on the first and third leg (figs. 13, 14). Organ 

 No. 3 may occur on either the anterior or posterior side of the tro- 

 chanter as on the second and first legs. Also No. 4 may lie on either 

 the dorsal or ventral surface as in the first and third legs. 



Organ No. 1 (figs. 13, 16) is a simple structure of three slits on 

 the first three legs while on the fourth there are only two slits in it. 

 These slits have about the same dimensions and the dilatations are 

 nearer the proximal end of the organ. The distal end of the slits 

 never come in contact with the line of articulation. No 2 varies 

 slightly in shape, number and position of the slits. In fig. 52 the 

 organ is from the ventral side of the first leg, while in fig. 53 the 

 organ from the anterior side of the second leg shows the slight 

 variation. The distal end never crosses the line of articulation. 

 No. 3 is more or less diffused (fig. 15), but on the first and second 

 legs the border completely surrounds the organ. Instead of the 

 long axis of No. 4 lying parallel with the long axis of the leg, it 

 lies transversely (fig. 30) and it always lies against the line of articu- 

 lation and sometimes one-half way across it. No. 5 on the ventral 

 surface at the extreme distal end of the femur always lies with 

 its distal end touching the line of articulation, but very seldom 

 crosses it. The convex part of the organ and the shorter slits inva- 

 riably face the posterior surface of the leg (figs. 13, 24). No. 6 is 

 like No. 5 except it lies on the dorsal side of the femur and usually 

 one-half way across the line of articulation (fig. 14). Its concave 

 side and shorter slits face the anterior surface of the leg. Organs 

 No. 7 and 8 (figs. 13, 14, 58) are always found on the anterior surface 

 of the patella. No. 7 (58a) lies almost equidistant from either 

 end of the joint near No. 8 (586) and always between the latter and 

 the dorsal side. Its size is almost one-half that of No. 8 and 

 its slits are very long and extremely narrow. No. 8 lies nearer 

 the distal end of the patella, usually very near the Hue of articu- 

 lation, but never against it. Its slits are much longer than those 

 in No. 7 and the smaller ones face the ventral surface as in No. 7. 

 One finds organ No. 9 at the distal end of the patella on the dorsal 

 side about 135 degrees from organ No. 7. It never touches the line 

 of articulation and is usually some distance from it. Its apex points 

 toward the angle formed by the line of articulation with the edge of 

 the anterior side. Its shorter slits always face the anterior surface 

 of the leg. One or two or no single isolates slits usually accompany 

 it and these occur near the concave side which faces the anterior 



