860 



INSECT. 



surface of the wing itself exhibits the appearance 

 when similarly examined, of numerous minute impreS' 

 sions arranged in lines, in which the base of the scales 

 are planted, being laid upon each other like the tile 

 on the roof of a house. The derivation of the name 

 of the order Lejiidoptcra (scaly wings), expresses this 

 character. It has been suggested that the form o 

 these scales might be serviceably employed in fur- 

 nishing specific characters, for the determination o 

 the various species of lepidopterous insects ; but this 

 is quite impossible, since scales of every possible form 

 are found upon a single individual, as may be seen 

 from the preceding figures, all of which represent 

 scales from the goat moths. 



Here it will be serviceable to notice a few of the 

 more characteristic variations which occur in the 

 markings of the wings of lepidopterous insects (see 

 fig. 134) ; these are, 



Spots (Macula:), which are r.atches of one colour 

 appearing ou the differently coloured wings 

 (134. a a). 



Dots (Atomi), which are very minute points of a 



different colour; when scattered over the entire 



surface of the wings they are said to be irro- 



rate (A). 



Puncta, gutta, pustula, and plaga, are words used 



for spots of various sizes. 

 Lines (Lin&z), narrow, generally straight marks of 



different colour (c). 



Streaks (Slnga?'), somewhat broader lines, gene- 

 rally transverse (d). 



Bands (Fascitz), broad transverse marks (<?). 

 Vitta is a longitudinal fascia. 



The four last terms are said to be undulated when 

 alternately curved like waves (/), and dentated 

 when toothed (0). 

 Annulets (Annutij, ring-like marks (Ji). 



Imaginary wing of a Butterfly. 



. 



Eyelets (Ocelli), circular spots upon a differently 

 co cured wing, with the centre also differently 

 coloured (,') . ,h e latter is termed the pupil 

 (papilla), and is surrounded by the iris 

 Luniileis (Liatulat), crescent-shaped marks (ft 

 Adjective, derived from these words are employed 

 m descnbing lep.dopterous and other insects. Thus 

 W e " W rdS a8 maculated ' frsciated, ocella- 



the 



fliC? ' th : win ? s are cl thed with fine 



/ na '\ e of the ord r give " to them b y 



p ' I 5 e Wln?s of the e nat areal *o 



ornamented with scales along the nerves 

 . - 



the posterior wings, the a 



margin ; the 



other side is named the apical, or terminal, margin. 

 There is, however, the greatest diversity in the shape 

 of the wings, especially the posterior pair in the 

 Lepidoptera ; some are notched, and many ter- 

 minated by one or more long tails. A small group 

 of moths have been termed Plumes, from the wings 

 being divided into numerous feathers, the divisions 

 extending to the base of the wing ; some are five- 

 plumed, and others twenty-plumed. 



Adjoining the external margin of the wings, at some 

 distance beyond their middle, a callous point is to be 

 observed, formed by the union of the nervures of this 

 anterior or costal margin, which is termed the 

 stigma. 



In our article HYMENOPTERA, we have noticed 

 more particularly the formation of the cells, origi- 

 nating in the nervures arising from the stigma, and 

 which have been much employed in distinguishing 

 the various groups of insects. That it is, in certain 

 families highly important, cannot be doubted ; but we 

 must not rely implicitly upon it as an absolute cha- 

 racter, since many groups, having very different habits, 

 and varying in other important characters, are iden- 

 tical in the neuration of their wings. The credit of 

 having selected these variations in the form of the 

 cells, as affording good generic characters, has ordi- 

 narily been given to Jurine, a celebrated Swiss ento- 

 mologist, who arranged the Hymenoptera in accord- 

 ance therewith. Frisch, however, a German, and 

 Harris, an English author, had long previously made 

 use of the same characters. 



In general, membranous wings remain expanded at 

 all times to their full extent, but this is by no means 

 a constant character. Thus in the Hymenoptera, the 

 family of the wasps (Fespidee), and the species of the 

 genus Leucospis, they are folded throughout their 

 whole length when unemployed. In the Lepidoptera 

 the same occurs in the family of the Plume moths, al- 

 ready mentioned. The lower wings of orthoptcrous 

 and homopterous insects, are also longitudinally fold- 

 ed beneath the wing covers ; and the wings of coleop- 

 terous insects, are folded both longitudinally and trans- 

 versely when unemployed. The posterior wings of 

 the Earwig are similarly folded, the nervures, when 

 the wings are extended, forming a most beautiful ob- 

 ject. The position of the wings when shut, afforded 

 to Linnaeus the chief character by which he divided 

 the moths into various sections. Thus they were said 

 to be depressed, deflexed, horizontal, extended, diva- 

 ricate, &c. 



Some lepidopterous insects appear to have six 

 wings, and have since been specifically named Hexa- 

 ptera/a, Src., forming the genus Lobopkora of Curtis; a 

 name indicative of the real character of the wings, of 

 which the posterior pair are furnished with a large 

 membranous lobe. 



It still remains for us to mention a small mem- 

 branous appendage connected with the base of the 

 wings in the majority of dipterous insects, to which 

 the name of alula, or vvinglet, is generally given, con- 

 sisting of two concave and convex membranes united 

 together, and surrounded by a fine fringe, which fold 

 over each other like the valves of a bibalve shell, and 

 ipon which we have seen the halteres act, in a man- 

 icr similar to a drumstick beating on a drum. Kirby 

 and Spence regard them as analogous to the poste- 

 rior wings ; but they are decidedly parts of, and cor*, 

 nected with, the large wings. Somewhat similar 

 organs have been noticed in the large water beetle, 



