DREDGING NOTES. 



tion to tip slightly toward the side that has not 

 enough support. The small dragon-fly larvae seem 

 to be a fraction less ferocious than the large ones, 

 and to them we owe a debt of gratitude, since 

 they make a point of consuming as many mos- 

 quito-larvae as can be obtained. 



The mask of the dragon-fly is somewhat like 

 that ancient implement known as a " catch-poll," 

 wherewith officers of the law were wont to appre- 

 hend criminals who were taking to their feet for 

 liberty. The poll- 

 part of the instru- 

 ment being about 

 six feet long was 

 fitted with an ingen- 

 ious steel apparatus 

 at the end consist- 

 ing of two V-shaped 

 arms and a collar. 

 The arms being flex- 

 ible the head of the 

 offender was allowed 

 to slip past them, 

 but when the collar 

 was once around his 

 neck he was securely held, and then the officer 

 calmly dragged his victim to prison, or pushed 

 him there, as suited the offended administrator 

 of the law. Some collars of the "catch-polls" 

 had rows of sharp spikes set round them,, so that 



Mask of Libellula dragon-fly larva. 



