388 INSECTA. 



The eighth tribe, that of the Byrrhii, differs from the pre- 

 ceding in the perfect contractility of the legs ; the tibiae are 

 susceptible of being flexed on the thighs, and the tarsi on the 

 tibias(l), so that when thus folded and pressed against the 

 body, the animal seems to be inanimate and entirely destitute 

 of feet. The tibiae are usually broad and compressed. The 

 body is short and convex. 



This tribe is chiefly composed of the genus 



Byrrhus, Lin. 

 Those species which form the 



NOSODENDRON, Lat. 



Are removed from the others by their entirely exposed, very large, 

 and scutiform mentum. Their antennae terminate abruptly in a 

 short, perfoliaceous and triarticulated club. They are found in 

 wounds of trees, of the Elm particularly(2). 



Byrrhus, Lin. Cistela, Geoff. 



The true Byrrhii differ from the preceding Insects in their men- 

 tum, which is of an ordinary size and interlocked (at least partially) 

 by the presternum, whose anterior extremity is dilated. 



In some, the antennas enlarge insensibly, or terminate in an elon- 

 gated club formed of from five to six joints. 



B. pilula, L.j Oliv., Col. II, 13, 1, 1. From three to four 

 lines in length; black beneath, blackish-bronze or soot-colour 

 and silky above, with little black spots mingled with lighter 

 ones arranged in lines. 



M. Waudouer has detected the larva of a variety of this spe- 

 cies. It is narrow and elongated; the head thick; the plate of 

 the first segment large, and the two last longer than the others. 

 It lives in Moss. 



A second species striato-punctatiis, Dej. with similarly 

 formed antennae, constitutes a separate division, on account of 

 its tarsi, of which the fourth joint is very small and concealed 

 between the lobes of the preceding one. 



The antennae of another species, very small and covered with 



(1) In the Anthreni all the tibiae fold against the posterior side of the thighs; 

 but in the others, the two that are anterior are flexed towards the head, and the 

 other behind. 



(2) Lat., lb., II, p. 43; Oliv., Encyc. Method., article Nosodendre. 



