1867.] 313 [Scudder. 



tT'trtrtT|ttrTrfr?|r?rir' 



Note of Stenobothrus melanopleurus in the shade. 



The stridulation of the Stenohotliri is never very distinct, but in 

 Arcyptera lineata, a very shy species, it can be heard at a distance of 

 fifty feet. These insects usually make four notes, but the number is 

 sometimes greater. The first, a quarter of a second in length, is 

 duller than the others, and followed by a pause of a quarter second ; 

 the other notes are of the same length, but sharjily sounded, and 

 follow each other rapidly. 



Note of Arcyptera lineata. 



Those Acrydii which produce sounds by rubbing their wings and 

 elytra together, stridulate only during flight, and are nearly all con- 

 fined to the genus (Edipoda ; their hind wings are often brilliantly' 

 variegated. These insects seem to have the sound under conti'ol, for 

 although they generally make it during flight, they may omit it when 

 frightened. Trafjocephala viridifasciata and LEdlpoda sordida produce 

 this sound during the whole of their undoviating flight; the note is per- 

 fectly iniiform. Gidipoda verruculata, cequalis and others, stridulate 

 only during intervals of flight, and seem to exercise the power more 

 at will; the flight of these insects is well sustained, and they are capa- 

 ble of changing their course; at each turn, they accompany the 

 movement with a swoop-like curve, and emit a crackling sound, which 

 lasts but a portion of a second. Q^dipoda Carolina makes a similar 

 movement, but accompanies it simply by a muffled, rustling sound. 

 Other species of (Edipoda, such as CE. pellucida, produce no sound 

 whatever. 



November 6, 1867. 

 The President in the chair. Sixty-three members present. 



Dr. B. G. Wilder spoke of symmetry and of distorted 

 symmetry in animals and plants, especially in the leaves of 

 the elms, and of the hop-hornbeam. 



