148 INSECTS. 



The mandibles (fig. 13) are curved, bifid at the apex, 

 and with a tooth on the inside near the base. The 

 labrum (fig. 14) is transverse, or broader than long. 

 The labium (fig. 12) is furnished with two palpi, which 

 are 3-jointed. The maxillae (fig. 16) are two-lobed, 

 the lobes (b, c) being ciliated, and the 4-jointed palpi 

 (a) have the last joint large and hatchet-shaped. 



Coleopterous insects undergo complete metamor- 

 phosis, the larvae being commonly known as grubs. 

 The larvae of the aquatic beetles will often be met 

 with in the water of ponds or ditches, especially that 

 of the common large water-beetle (Dytis'cm margi- 

 ndlis), or water-boatman as it is called (PI. X. fig. 7), 

 and in various stages of growth. The structure of 

 the mouth-organs (fig. 6), which are, however, im- 

 perfect or rudimentary in some parts, can be readily 

 made out ; and their names may easily be found by 

 comparison with what has been stated in regard to 

 the organs of the perfect beetle. 



Examination, fyc. The means of catching insects 

 will readily occur to the reader. A bag-net made of 

 a curved piece of cane, to which is fitted a bag made 

 of net, will serve to catch those which trust to flight 

 for escape from their enemies, such as the Lepidoptera; 

 and these may be killed by firm pressure of the thorax 

 between the finger and the thumb. The running 

 insects, as the beetles, may be caught in a spoon or 

 with forceps ; and they may be killed by immersion 

 in boiling water or in camphorated spirit. In an 

 excursion, most insects may be carried in a well- 

 corked bottle containing a little wool and a lump of 

 camphor, which stupifies them. When the insects 

 are dead, the limbs should be extended into the na- 

 tural position by means of pins, the insect being 

 transfixed by a pin run through the thorax or one of 

 the elytra and extending into a sheet of cork. To 

 preserve them, they may be kept in a box, the bottom 



