IQOl] ENTOMOLOGICAL NEWS. 281 



Thus the wings are pressed upward against the elytra by the 

 raising of the abdomen, the spinous areas described are rubbed 

 across the specialized portions of the wing- folds and this pro- 

 cess results in the production of the sound. 



All the specimens studied, over a hundred in number, pro- 

 duced apparently the same sound. Among these occurred both 

 males and females as determined by dissection. The observed 

 stridulation occurred only when the beetle was disturbed. These 

 facts would lead to the conclusion that it was evidence of the 

 insects' displeasure at being disturbed and not a sexual call, 



EXPLANATION OF PLATE XII. 

 Fig. I. — Dorsal surface of the abdomen (x 11) : A, stridulating areas. 

 Fig. 2. — Portion of surface of Fig. i, A (x 350). 

 Fig. 3. — Vertical section of Fig. 2. 

 Fig. 4. — Under surface of the hind portion of one wing showing the part 



rubbed by the stridulating area (x 11) : A, representing the 



strongly chitinized and ridged vein. 



Letters from Thomas Say to John F. Melsheimer, 

 J8I6-1825.— VIII. 



Philad? March 13*'? 1819. 

 My dear Sir ! 



I have been so continuously occupied in preparing for our 

 Western Expedition that I have hardly time even to write to 

 my friend at parting. If I recollect rightly I informed you of 

 our destination to examine all the immense Western waters — 

 the Mississippi, its tributaries, some of the Lakes & perhaps 

 some of the rivers still further south — Besides my own depart- 

 ment, viz. Zoology, we shall be accompanied bj' a Botanist 

 (D^ Baldwin), a Geologist & Mineralogist (M^ Jessup), & 

 M^ T. Peale will accompany me to prepare the skins of such 

 animals as may be discovered. Our Commander Major Long 

 has furnished himself with the necessary instruments for As- 

 tronomical and other observations ; so that I think we shall go 

 well prepared — Our Steamboat at Pittsburg is nearly ready & 

 it is ordered that we depart from Philad? in all next week — It 

 is further determined that we shall return to Pittsb? to winter 

 next season — All this is inter nos. 



