580 THE MICROSCOPE. 



largest it extends beyond the limits of our conipreliension, 

 escapes our researches in the smallest. If, while we dis- 

 sect with care the larger animals, we are filled with wonder 

 at the elegant disposition of their limbs, the inimitable 

 order of their muscles, and the regular direction of their 

 veins, arteries, and nerves, to what a height is our astonish- 

 ment raised when we discover all these parts arranged in 

 the least of them in the same regular manner ! How is 

 it possible but that we must stand amazed, when we retiect 

 that those little animals, whose bodies are smaller than the 

 point of the dissecting knife, have muscles, veins, arteries, 

 and every other part common to large animals ! Crea- 

 tures so very diminutive that our hands are not delicate 

 enough to manage, nor our eyes sufficiently acute to see 

 theni." 



The Articulate sub-kingdom, family Inseda, is divided 

 and sub-divided into many genera, the principal of which 

 are — 



Lepidoptera ; typical form, Eutterhy, Moth. 



Dipteria;^ typical form, Fly, Gnat, &c. 



Aptera ; typical form. Flea, Louse, Springtail. 



GoleojJtera ; typical form. Beetle, Water Beetle, &c. 



OrthopUra ; typical form, Locust, Grasshoj)per. 



Neuroptera ; typical form. Dragon-fly, May-fly. 



llymenoptera ; typical form, Bee, Wasp, Ant, 



Homop)tera ; typical form, Plant-louse (Aphis), Lan- 

 tern-fly. 



IIemip>tera ; typical form, Water-scorpion, Water-boat- 

 man. 



Ay^achnida ; typical form. Spider, Scorpion, Szq. The 

 Acarina \i(d\ong to this genus, family ^ career, well known 

 as " Mites " and " Ticks." 



Insects are characterised by a simple breathing ap- 

 paratus ; by the division of the body into distinct regions 

 or segments ; when three, the middle one, the thorax, 

 bears three pairs of jointed legs, and usually two pairs 

 of wings ; and by the possession of a single pair of jointed 



(1) Comprised \vithin the order Diptera, or two-winged flics, arc several 

 genera having no wings, tlie apterous and suctorial Pulex, and the aptorons and 

 pupipurous JCpuhoscidce: anions; the hitter, we have the winged Hippobosca, or 

 horse-Ily, and ssonie others. 



