LIFE-HISTOET OF CEOCE FILIPENNI8. 



157 



Meinert * in the larvae of Myrmeleon and Hemerobius. Completely suctorial mandibles 

 have been described by Schiodte f in the larva of the European Coleopterous insect 

 Gyrinus marinus, and they have been long known in the larva of Dytiscus marginalia 

 from the early observations of Swammerdam % and later by De Geer, and more recently 

 by Miall and by Burgess. Gyrinus and Dytiscus differ from the larvse of the 

 Hemerobiidse in that the maxillse are not specially modified, nor do they aid in per- 

 forming any suctorial function ; but the mandibles are perforated by a minute pore close 

 to their apices, and this leads into a channel passing through the centre of each mandible 

 to the mouth. 



The larvse frequent disused or neglected rooms and outhouses, living on the floor 

 among accumulated sand and dust. In such situations Psocids are extremely plentiful, 

 and I believe that they form their principal prey. In their habitat the larvfe are well 

 concealed by a covering of particles of sand and dust. They cover themselves by 

 pushing the posterior end of the abdomen into the latter, and bury themselves until only 

 the head remains visible. They afterwards emerge with a coating of such particles, which 

 are to a large extent kept in position by the numerous dentate spines covering the body. 

 Thus concealed, the larva remains motionless for long periods, until it may dart forward 

 to seize some prey that may wander in its vicinity. It was a matter of great difficulty 

 to discover the larvse when the habitat was only suspected and not definitely known. 

 The first larvae were met with in July 1907, and the most advantageous way of detecting 

 them was to examine a quantity of sweepings from the floor of a neglected room 



* " Om Mundens Bygning hos Larverne af Myrmeleontiderne, Hemerobierne, og Dytiscerne," Vidensk. Medd. 

 Nat. Foren. 1879, p. 69. 



t " De metamorphosi Eleutheratorum, Bidrag til InsekternesUdviklings-historie," Kroyer, Naturh. Tikskr. 1862. 

 % ' Biblia Naturae,' vol. i. p. 325. 



