692 EXTERNAL ANATOMY OF INSECTS. 



longer than the claw-joint. With regard to their curva- 

 ture they generally form the segment of a circle ; in many 

 Asilidce they are crooked like the claws of the eagle % 

 and the posterior one of the Hoplite is bent like a hook b ; 

 they most commonly diverge from each other ; but in 

 the Rutelidce, Anoplognathidce, &c, they are perfectly 

 parallel, and in the former often inflexed c . With regard 

 to other appendages of the part we are treating of, if you 

 examine the stag-beetle and many other Lamellicorns, 

 you will find between the claws a minute but conspicuous 

 joint terminated by two bristles which seem to mimic 

 the ungula and its claws ; these parts are what are deno- 

 minated in the table the palmula, plantula, and pseudony- 

 chia: in the stag-beetle these are long d ; in the Melolon- 

 ihidcB short e ; and in many Cetoniadce they resemble an 

 intermediate claw. 



The most remarkable of the appendages of the tarsi are 

 to be looked for on their under side or sole (solea), and 

 are the means by which numbers of insects can overcome 

 atmospheric pressure and walk against gravity. Many 

 of these have been fully described in a former let- 

 ter f ; but much that relates to them was there omitted, 

 which I shall now detail to you. Four kinds of pulvilli, 

 as I would call these appendages, are found in the sole 

 of insects, upon each of which I shall makea few remarks. 



Thejirst is a cushion or brush composed of very thickly 

 set hairs or short bristles : examples of this you will find 

 in the majority of Tetramerous and Trimerous beetles. In 

 Chrysomela, Timarcha, &c, there is one of these cushions 



* Plate XXVII. Fig. 53. b i b j d . FlG> 5] 



C Ibid - FlG - 4 7- d Ibid. Fig. 56. a-1, f* 



* Ibid. Fig. 49. a+,f\ t y ou U . p. 32G-. 



