COLEOPTERA. — DYTfCID^.. 99 



Stated to leave the water and to hibernate beneath moss and lichens. 

 The union of the sexes takes place in the autumn or at the beginning 

 of spring ; the female deposits her eggs from time to time, each laying 

 consisting of from forty to fifty eggs, which are long and cylindric, and 

 deposited in the water at random, the larvae being hatched in the 

 course of a fortnight. 



The larva of Dyticus marginalis, according to Rosel, is very active, 

 and when four or five days old is about four or five lines long, when it 

 casts its skin for the first time. The second moulting takes place at 

 about the same distance of time, and when the larva has increased about 

 twice its former size, and it continues to grow and cast its skin (ten 

 days intervening between each moulting, according to P. Lyonnet,Me»i. 

 p. 109.), until it is two inches long, when it has attained its full size 

 ^fi9' 5' 14.). The exuviae may often be observed floating on the water, with 

 the mandibles and caudal appendages attached to them. These larvae, 

 which have long been known under the names of Squillae or Shrimps, 

 are of a dark ochre or dirty brown colour, with the body long and sub- 

 cylindric, slenderer at each extremity, but more especially towards the 

 tail, and consisting of eleven segments, exclusive of the head; the first 

 nine segments are somewhat scaly above, but fleshy beneath ; the 

 first segment is longer and narrower than the following, and represents 

 the prothorax of the imago ; the sixth, seventh, and eighth are larger 

 than the others, which are of nearly equal size; and the two terminal 

 joints are long and conical, the apex being slightly truncate and scaly, 

 with the sides fringed with hairs, whereby the insect is enabled to swim 

 along in the water; these joints serving both as an oar and a rudder, 

 and imparting a worm-like motion when the tail is moved in various di- 

 rections. The terminal segment is provided with apair of long and slen- 

 der pilose appendages, whereby the insectis enabled to suspend itself at 

 the surface of the water, which, as Swammerdam says,flows from them 

 on every side, and thus the suspension is effected. These apj)endages, 

 moreover, are tubular*^ and comnmnicate with the air vessels which run 

 along the sides of the body, which is moreover furnished with sixteen 

 spiracular points, which, however, from the observations of Lyonnet, 

 appear to be but rudimental, not becoming aerifcrous until the period 

 when the insect puts off its larva state. The head in these larvae is 



* I^atreillo and Dc Gcor, liowever, nicnlioii two atlditional bodies of small size 

 and cylindric form, each having a distinct si)irack-, and placed at the extremity of the 

 body, at the base of the long and slender filaments. 



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