40 



NATURAL HISTORY OF INSECTS. 



wings (Figs. 121 and 122),* and also the body and its mem- 

 bers, thickly covered with flattened scales of various patterns; 

 it is these scales which give the diversified colors to the 

 insects. When these scales are rubbed off, the wings are 

 found to be of a more or less membraneous texture (Fig. 123).f 



Fig. 123. 



Fig. 124. 



In the Bees, Wasps (Fig. 1), Two-winged Flies (Fig. 124), 

 Dragon-flies, Plant-lice and similar insects, all the wings are 

 thin and membraneous; as are also the posterior wings in 

 those insects which have the anterior pair thickened (Fig. 

 114, 6). The wings of the former kind are usually furnished 

 with several veins (Fig. 125)J, which are more or less closely 



. Fig. 125. 



connected with each 

 other with cross-veins 

 or nervures. These 

 veins and cross-veins 

 form several enclosed 

 spots, which may be 

 likened to the panes 



* EXPLANATION OF FIG. 121. ab, inner third of wing: am, middle third: al, outer 

 third; A, costal edge; B, inner or posterior edge, C, outer edge; D, apex; sd, basal 

 line; sa, transverse anterior line; mo, orbicular; mr, reniform; um, transverse shade; 

 sp, transverse posterior line; ms, marginal line; Ib, dentiform spot. 



* EXPLANATION OF FIG. 122. (Capitals, same as in Fig.121) ; fr, frenulum , em, lunule. 



t EXPLANATION OF FIG 123. (Capitals same as in Fig. 121); a, antenna; 1, pro- 

 thorax; m, patagia; k, mesoscutum; ab, discal cell; am, discal cross- vein; above al, 

 independent vein; -n, abdomen. 



J EXPLANATION OF FIG. 125. c, costal vein : sc, sub-costal vein , TO, median vein; 

 sm, sub-median vein, i, internal vein; 1, costal cell; 2. (dark) stigma; 3, marginal or 

 radical cell , 1, 2, 3, A, (back of stigma and marginal cell) sub-marginal or cubital 

 cells, 2, 3,4, (back of sub-marginal cells) discoidal cells. 2, 3, inner and outer apical 

 cells; 1, 1, 1, (nearestthe base) median, sub-median and internal cells; c, the apex. 



