INTRODUCTION. 69 



with several, often very vivid and strongly con- 

 trasted. Sometimes they are distributed in rays or 

 longitudinal stripes, at other times in bands which 

 follow the contour of the rings ; often in waves or 

 spots of regular or irregular figure ; and not unfre- 

 quently in insulated points, and numerous other 

 forms too complex and varied to admit of being 

 here particularised*. It frequently happens that 

 the colours of larvae, before their first moult, are 

 entirely different from those afterwards assumed ; 

 and in some instances they undergo a considerable 

 alteration at every successive change of skin. Dif- 

 ference of colour, in individuals of the same species, 

 sometimes indicates the respective sexes of the 

 future moth ; thus, according to De Geer, the brown 

 caterpillars of a common species, the Yellow Un- 

 derwing ( Triphcena pronuba) produce males and 

 the green ones females. 



Many of these caterpillars are distinguished by 

 horns and protuberances of various sorts, which add 

 greatly to the singularity of their aspect. The 

 curious caudal appendages of those of the Puss and 

 Lobster moths have been already alluded to, and will 

 be more particularly described hereafter. Several 

 have a kind of horn on the hinder extremity, some- 

 thing resembling that of Hawk-moth Iarva3, but 

 it is never so long and acute as in the latter, at 

 least among British species, but rather assumes the 

 form of an elongated tubercle. An example of this 



* Reaumur, Memoirs pour servir a Vhistoire des Insectes^ 

 torn. i. page 76. 



