SC/ENCE-GOSS/r. 



17 



much loni;L'r in ihc hind-win^ ; ( k) the siilnuslul 

 lurfiin is iiiiiniriliatcly below, ll };ivc'S iilf several 

 branches, generally four or live on ihe fore-wings, 

 1)111 sometimes less. These are called subcostal 

 nervules (f,\ *", <"', h^\ I,'). On the hind-wings Ihe 

 subcostal only gives off one secondary branch ; or 

 father, itself bifurcates. 



Helow the subcostal nervurc is a large s[xice called 

 the ,lisioi(i<il tell. It is formed by the subcostal above, 

 and the median nervure below. This space is some- 

 times closed at its outer end by an anastomosis of 

 these two nervures, as shown in the figure, though at 

 other limes it is open. The discoidal cell is closed in 

 I'apilionidae, I'ieridae, Uanaidae, Satyridac, and in 

 some genera of other families. 



I'Vom the discoidal cell, or prolonged from the 

 siihiiiii/iaii, two nervules are given off on the fore-wing 

 and one on the hind-wing (i, <'). These are called 

 upper and lower discoidal nervules. 



Ne.xt is the median ncn-ure ((/), giving oft" one 

 median nervure in the fore-wing (d') and (W d") on 

 the hind-wing. Below this is 

 the siibiiudian nervure (<^) which 

 is without ramifications. Lastly 

 the hitirnal lurvtin (f) which 

 is either absent, as in the figure, 

 from the front-wing, or else is 

 very short. 



The wing-membranes them- 

 selves are furnished with minute 

 depressions or sockets, arranged 

 in regular rows. Into these are 

 inserted the scales, thai clothe 

 the wings, and which give the 

 name to the order Lepidoptera 

 or " scale-winged" insects. The 

 scales are usually placed closely 

 together, overlapping oneanother 

 like the tiles on a roof, giving a 

 dense clothing to the wings. 

 The scales are usually of an 



ovoid or oblong form, at times truncated at the upper 

 end, andoccasionallydentated or serrated. Sometimes 

 they are elongated. They are furnished at the inferior 

 extremity with a stalk or short process by which they 

 are in.serted in the wing follicle or socket. The body 

 of the scale is said to consist of two layers of 

 membrane between which are exceedingly minute 

 panicles of pigment granules. The surface of the 

 scales is sometimes striated in such a manner as to 

 produce the effect of iridescence, or fluorescence, by 

 heir refracting action. To this we may attribute the 

 beautiful iridescence we see in Apaliira iris, and 

 some other species. Also the metallic effects of the 

 silvery decorations in genera such as Ar,i;yniiis, and 

 the brilliantly shining colours of many of the 

 Lycaenidae The scales themselves are so minute, 

 when examined by the unassisted eye, as to 

 resemble gr,ains of dust ; but their fonii is apparent 

 even under a low-power microscope. 



Most butterflies have their wings densely clothed 

 with scales, though some are l)ut sparsely provided 



Tkr^unoia 



with them ; as in the genera J'uriiasiiiii and Ooriln. 

 .\mong the I'alaearctic Butterflies, there arc no 

 actual " cloiir wings" like some of the Tropical 

 lleliconi<lae, I'ieridae, and also Erycinidac and 

 .Satyridae. 



In Thaii riiiiiina and T. iiiei/fsirasle, there are 

 transparent patches near the apex of the fore wings, 

 and some of the Siberian Hesperidav have nearly 

 transparent markings. 



The arrangement of the colouring and pattern of 

 the wings is very various. Sometimes it has relation 

 to the neuration, but very often not. When this is 

 the case, the design is in the form of lines, as in 

 Papilio mai/moii, many Pieridae, Danais erifipiis, 

 etc. 



Marginal and sub-marginal borders and liands are 

 very common, as again in /'. machaon, the genus 

 Colias, etc. I'asciae or bands of colour crossing the 

 wings are often seen, as in Limcititis sil'ylln and 

 I'aiiissa a/alaiila, etc. Occasionally, a patch of 

 colour is spread over a large portion of the wing area, 

 as in KIwdocera ileofia/ra, and 

 in the females of '/'/utlai/ncriiis. 

 The apices of the fore-wings 

 are often marked with white 

 spots, as in many of the Nymph- 

 alid.-ie. Spots are indeed the 

 most common form of markings. 

 These are either rectilinear in 

 outline, spherical, or ovoid. 

 They are sometimes spread over 

 ihe whole surface of the wings 

 as in 'I'hnis, Melilaea and 

 Argynnis, usually, however, 

 they have a limited and definite 

 disposition ; aspotinlhediscoidal 

 cell being characteristic of many 

 genera. For example, the black 

 spots in the discoidal cell on the 

 imderside of the genus Lyiaeiia, 

 and the single red spot seen on 

 each wing of A'Aodoccni r/iai/mi. Very commonly 

 spots are disposed in rows running [Xtrallel with the 

 outer margins of one or both pairs of wings. This is 

 seen in genera too numerous to mention. Ocellated 

 or pupilled spots are very ctmimon. especially in the 

 Nymphalidae, Lyc.ienidae and Satyridae. In many 

 species there is a well-marked ocellated spot near the 

 anal angle of the hind-wings. In the genus 

 /'aniassitis anmdar spots, generally red in colour, are 

 nearly alw.iys present on the hind-wings. Lunules 

 are spots of a crescentric shape, and are usually dis- 

 posed in rows parallel with the outer margin. 



.Metallic silvery markings are found on the under- 

 side of many Lycaenidae as in Cigtiri/is iM\i\ Lyttn-tia. 

 In Ihe latter they often form the centres of the 

 suliniartMnal spots of the hind-wings. These have 

 received the name of " peacock eyes" from some 

 writers. It is, however, in the genus Argj'iiiiis that 

 the silvery markings are most evident. They 

 generally take Ihe form of blotches or spots, 

 diflerenily disposed on the wing area, and mostly 



I>i.\i;K.\>t or Hi rTlCRl-l.v 



