1SG STATES OF INSECTS. 



longitudinal rays or bands, at others in transverse ones. 

 Sometimes they are waved or spotted, regularly or irre- 

 gularly ; at others they are sprinkled in dots, or minute 

 streaks, in every possible way. Various larvae are of the 

 colour of the plant on which they feed, whence they are 

 with difficulty discovered by their enemies. Thus, a large 

 proportion of Lepidoptera are green of different shades, 

 sometimes beautifully contrasted with black bands ; a cir- 

 cumstance which renders the caterpillars of two of our 

 finest insects of this order as lovely as the fly : I mean 

 that of Papilio Machaon and Satumia Pavonia. Very 

 frequently the larvae of quite different species resemble 

 each other so exactly, in colour as well as shape, as 

 scarcely to be distinguishable : this sometimes takes 

 place even where they belong to different genera, as in 

 those of Bombyx versicolor a moth, and Smermthus Po- 

 puli a hawk-moth. And it sometimes happens, very for- 

 tunately for distinguishing allied species, that where the 

 perfect insects very nearly resemble each other, the lar- 

 vae are altogether dissimilar. Thus, the female of Pieris 

 Rapce is so much like the same sex of Pieris Brassicce, 

 that it might be taken for a variety of it, did not the 

 green caterpillar of the one, and the spotted one of the 

 other, evince the complete distinction of these butterflies. 

 Noctua Lactuca, N. umbratica, and several other species 

 of the same tribe, which includes N. Absinthii, Verbasci, 

 Chamomillce, Abrotani, are so extremely alike, that the 

 most practised eye can scarcely discover a shade of dif- 

 ference between them, though their larvos in colour and 

 markings are constantly distinct 3 . The markings of 



• Wien. Vera. 219. 



