6 Illinois State Laboratory of Natural History. 



stituting a removable plug for the turncock in the Apstein 

 bucket, and differs from both in the base and in the manner 

 of attachment of the silk in the windows. 



In form it is a cylinder 7 cm. in height and 4 cm. in out- 

 side diameter. (Owing to the material available for construc- 

 tion our bucket measures 4.4 cm. in outside diameter.) It 

 consists of three pieces : the head-piece, the bucket proper, and 

 the band clamp. 



The head-piece of the bucket (Plate II., Fig. 3, h. p.) is a 

 cylinder 2 cm. in height, whose upper edge is rounded upon 

 the inner face. The lower edge is threaded at m (Fig. 3) so 

 as to screw into the top of the bucket proper, which is corre- 

 spondingly threaded at n (Fig. 4). The screw is so con- 

 structed that the inner surface is uninterrupted when the bucket 

 proper is fully screwed on. The head-piece also bears three 

 equidistant eyes (Fig. 3, e.), in which are tied the three stay- 

 lines (s. I.) which pass up to the large, and then to the small, 

 rings of the net, and finally unite with the draw-line (Plate 

 III., Fig. 6, d. /.). The position and manner of attachment 

 of these stay-lines can be seen in Plate II., Fig. 3, and in Plate 

 III., Fig. 6. The net is clamped on the head-piece by the 

 circular net clamp (Plate II., Fig. 3, n. c), which is a band 

 of brass 1 cm. in width. To the ends of the band are attached 

 wings (w. n. c), which are approximated by means of a 

 thumb-screw (/. s.). By this operation the silk beyond the 

 line rs (Fig. B.) is firmly clamped between the brass band of 

 the net clamp and the head-piece of the bucket. 



The bucket proper (Plate II., Fig. 4 and 5) is a brass cylin- 

 der 5 cm. in height, and of the same diameter inside and 

 out as the head-piece. In the side of the bucket at a height 

 of 2 cm. are cut three windows 2.5 X 3.5 cm. These windows 

 are closed by a band of No. 20 silk held in place by a band 

 clamp, in which are windows similar to those in the wall of 

 the bucket. The bucket was constructed from a heavy piece 

 of brass tubing, the bottom (Fig. 4, b.) being inserted in the 

 following manner. The tube is turned out to the shoulder 

 (Fig. 3, sh.) and heated in a jet of steam, and while still hot 

 the piece of brass from which the bottom (b.) is finished, is 



