396 ORDERS OF PTILOTA. 



other sphingidae or hawk-moths, have obtained these names 

 from this kind of resemblance, whilst some of the larger 

 exotic moths, and especially the gigantic Brazilian Erebus, 

 which measures nearly a foot across the wings, have mark- 

 ings on their wings, which have induced the name of Strix 

 (owl) to be applied to the last-named insect; and every 

 school-boy knows that the name owlets or owlards is given 

 to large pale-coloured thick-bodied moths, such as the puss- 

 moth, which fly about in the twilight. 



The legs of these insects are slender and hairy, offering, 

 in many species, various remarkable peculiarities in the dif- 

 ferent sexes, which have not hitherto been sufficiently ex- 

 amined. In general, the six legs are alike, but in some 

 butterflies, which have thence been termed Tetrapodes, the 

 fore-legs are either very small, or occasionally rudimental. 

 In the majority of these insects, the only difference between 

 the males and females consists in the larger size of the latter, 

 and especially of the abdominal portion of the body. The 

 colours of the males are, however, often more brilliant, and 

 the markings more decided, than in the other sex. In some 

 species of moths, the wings in the females are very short, 

 and quite unfitted for flight, and in others they are entirely 

 obsolete. Some females, in this case, also much resemble 

 their larva?, such as those of Psyche and Oiketicus. Various 

 differences also exist in the colours of the opposite sexes, as 

 in the orange-tip butterfly, of which the males have the tip 

 of the anterior wings orange-coloured, no trace of which is 

 to be seen in the females ; or still more strikingly in the 

 ghost-moth {Hepialus humuli) ; or the mushn-moth {Arctia 

 meudica), in which the colour of the wings is entirely dif- 

 ferent in the opposite sexes. Many instances have been 

 observed, in which the same specmien has exhibited the 

 characters both of the male and female insect, half of the 

 body being mascuhne, and the other half feminine ; and I 



