EXTERNAL ANATOMY OF INSECTS. 64<3 



the anterior margin, of the prominences before mentioned, 

 into a spathula-shaped diverging process, varying in 

 length and width a : but in P. Ulysses it does not diverge ; 

 and in P. Podalirius it is linear. They are found also in 

 other subgenera; thus in Urania Patroclus there are two; 

 in U. Riphceus three; in Erycina Cupido flve ; and in 

 E. Endymion six of these tails ; in some, as in E. Doryfas, 

 the whole wing seems to form the tail ; in others again, as 

 in Hesperia Proteus and Bombyx Luna, it is an elongation 

 of the anal angle. Other wings in this Order are divided 

 into lobes resembling feathers, as you may see in Ptero- 

 phorus hexadactylus, &c. b 



6. We are next to consider the clothing -of wings: these, 

 in the Orders in which they are covered by elytra, teg- 

 mina, or hemelytra, are generally naked, except that the 

 spots in those oiEidgora laternaria, serrata, &c, and the 

 whole wing in Plata, Aleyrodes, and others, are covered 

 with a kind of farinaceous powder; but in all the remain- 

 ing Orders, hairs or scales are more or less implanted in 

 these organs: as the Lepidoptera are the most remarkable 

 for the clothing of their wings, I shall leave them till 

 the last, and begin with the Neuroptera, If you lightly 

 pass your finger over the wing of any dragon-fly (Libel- 

 lula F., jEshna F.), from the apex towards the base, you 

 will find that the longitudinal nervures are, as it were, 

 serrulated with very minute bristles, which point towards 

 the extremity ; if you next move the finger across the 

 wing, from the posterior to the anterior margin, a simi- 

 lar circumstance will strike you. M. Chabrier conjec- 

 tures that, amongst other uses c , these hairs may contri- 



J Plate XIV. Fig. 1. «. b Ibid. Fig. 3. 



1 For some uses of hairs, see above, p. 399 — . 



2 T 2 



