INSECTS. 



[ 362 ] 



INSECTS. 



stuck into the leaded cork ( Intro d. p. 

 xxiii). 



The smaller and more delicate insects, 

 aquatic larvae, &c., are best preserved in so- 

 lution of chloride of calcium or glycerine, 

 mounted in suitable glass cells. 



To preserve insects for the future exami- 

 nation of the internal structure, they should 

 be kept in solution of chloride of zinc ; but 

 when very soft and fragile, they may be kept 

 in spirit and water. 



Insects are divided into two sections, and 

 these into twelve orders, thus : — 



Section 1. Apiropoda. 



Char. Legs numerous; thorax not sepa- 

 rated from the abdomen. 



Ord. 1. Myriapoda. Wings absent; legs 

 numerous (24 or more), terminated by 

 a single claw; eyes collected into two 

 groups, variable in number, sometimes 

 absent (fig. 366). 



Fig. 366. 



lulus terrestris. Magnified 2 diameters. 



Section 2. Hexapoda. Legs six ; thorax 

 distinct from the abdomen. 



Ord. 2. Thysanura. Wings absent; not 

 undergoing metamorphosis ; not parasitic; 

 mouth furnished with mandibles and 

 maxillae ; eyes simple, in two groups ; ab- 

 domen mostly terminated by setse or a 

 bifid tail. 



Ord. 3. Anoplura or Parasitica (Lice, PI. 

 28. figs. 3-8). Wings absent ; not under- 

 going metamorphosis; parasitic (eyes 

 two, simple, sometimes none). (See 

 errata.) 



Ord. A. Suctoria or Siphonaptera (Fleas). 

 Wingless ; metamorphosis complete ; 

 mouth suctorial; rostrum composed of 

 two serrated laminae and a thin suctorial 

 seta, included in a jointed two-valved 

 sheath. 



Ord. 5. Strepsiptera or Rhipiptera. Males 

 with four wings ; anterior wings two small 

 moveable corpuscles; posterior wings 

 large, membranous, in the form of a qua- 

 drant of a circle, longitudinally folded like 

 a fan. Females, apterous, vermiform, 

 without legs. Metamorphosis complete ; 

 mandibles two, narrow, somewhat curved ; 

 palpi two, biarticulate, far apart, inserted 

 beneath the head (larvae, pupae, and 

 females living parasitically in Hymeno- 

 pterous insects). 



Ord. 6. Diptera (Flies). Wings two, with 

 alulets at the base ; two halteres ; mouth 



suctorial ; labium not furnished with palpi, 

 prolonged into a proboscis or sheath, and 

 enclosing setae, variable in number ; palpi 

 (maxillary) two, at the base of the pro- 

 boscis; metamorphosis complete. 



Ord. 7- Hymenoptera (Bees, Wasps, &c.). 

 Wings four, membranous, posterior ones 

 smaller, and with fewer veins; maxillae 

 elongate, generally slender, sheathing the 

 labium ; abdomen of the females almost 

 always terminated by a borer or a sting ; 

 metamorphosis complete (fig. 367). 



Fig. 367. 



Tenthredo nassata. 

 Magnified 2 diameters. 



Ord. 8. Lepidoptera (Buttei*flies, Moths). 

 Wings four, membranous, covered with 

 coloured scales ; mouth furaished with 



