94 A Guide to the Zoological Collections in the 



the underlying juices. An enlarged drawing of the mouth- 

 parts is shown in the series in Case 97C. 



This large Order includes (i) the wingless Lice, the 

 Plant-lice, and the Lac and Cochineal Insects, which to- 

 gether constitute the sub-Order Hemiptera Aptera ; {2) 

 the Cicadas, in which both pairs of wings are well developed 

 and are usually membranous throughout, constituting the 

 sub-Order Hemiptera Homoptera ; and (3) the Bugs of all 

 kinds, which have the bases of the fore-wings hard and horny, 

 and form the sub-Order of Hemiptera Heteroptera. 



vi. HEXAPODA DIPTERA. 



This large Order includes the common Flies, the Flesh- 

 flies, the Gad-flies, the Gnats, Mosquitoes, and Crane-flies, 

 and the wingless Fleas. In all, the mouth-parts are modified 

 for piercing and sucking, as is shown in the enlarged draw- 

 ing in Case 97C, and only one pair of wings — the fore- 

 wings — is developed, the hindwings being reduced to small 

 knobs known as "halteres". In the Fleas both pairs of 

 wings are microscopic rudiments. 



vii. HEXAPODA LEPIDOPTERA. 



[(Ea0£0 98^ t0 125(E]. 



This very large Order includes the Butterflies and 

 Moths, in which the mouth-parts are peculiarly modified to 

 form a sucking-tube or " proboscis " as already described 

 (see also Case 97C). Both pairs of wings are well devel- 

 oped, except in the females of a few species of moths, in 

 which the wings are quite rudimentary, and are partially or 

 completely covered with the microscopic scales and hairs 

 that form the beautifully variegated coloration of the but- 

 terfly's wing. The metamorphoses of these insects are 

 too familiar to need further mention. 



The Lepidoptera are divided into two sub-Orders, name- 

 ly (i)the Rhopalocera, or Butterflies, (Cases 98A to 115A) 



