CARNIVOROUS INSECTS 115 



for them in country lanes and above the surface of ponds. The 

 legs of a Dragon- Fly are set on very far forwards, and this is 

 believed to be related to one of their functions. Just as some 

 bats use part of their flying membranes as a kind of sweep-net 

 for securing insects on the wing, so would it appear that the 

 dragon-fly's legs are forwardly directed during flight, acting 

 as a sort of fly-trap, the efficiency of which is increased by the 

 presence of numerous minute spines. Once entangled in this 

 trap there is no hope of escape, for the aggressor brings his well- 

 ■developed mouth-parts into play and conducts further operations, 

 which result in the rejection of the wings and other inedible 

 parts of the prey, and the retention of its more succulent portions 

 for food. These acts are facilitated by the mobility of the 

 dragon-fly's head, and the structure of its mouth-parts, which 

 include a freely-movable upper lip, and a lower lip provided with 

 two broad plates bounding on the, under side the space within 

 which the powerful mandibles and first maxillae work from side 

 to side. The rapacity of the aquatic larval form is even greater 

 than that of the adult. It is a sluggish, by no means attractive- 

 looking creature, thus described by Fred Smith (in The Boyhood 

 of a Naturalist) : — " And look here, here's the larva of a dragon- 

 fly, a thing I can't help having a perfect horror of; it seems to 

 me to be so truly hideous. It is like the nightmare of a horrible 

 scorpion — I mean the Egyptian thing. Its legs, and glorious 

 body, and wings that are to be, are now indescribably ugly, and 

 as though made of dirty putty." Yet this same object is possessed • 

 of a most interesting and curious apparatus, by means of which 

 it traps small crustaceans and any other animals of reasonable 

 size that come near enough. This is the so-called " mask ", which 

 is thus named because when not in use it is folded up in front 

 of the face, much in the same way as an old-fashioned carriage- 

 step. It is in reality the much-elongated lower lip, and can be 

 rapidly shot out at the prey, which is seized by a couple of 

 movable spiny projections at its tip, and then drawn back to 

 the well-armed mouth. 



May-Flies and Stone-Flies. — The May-Flies (see vol. i, 

 p. 375) and their allies [Ephemerids) are almost proverbial for 

 the brevity of their existence in the adult condition, though 

 there has been a good deal of exaggeration about this. It is 

 doubtful whether they take any food at all, at any rate the 



