STATE AGRICULTURAL SOCIETY. 409 



GRAPE. LEAVES. 



veins. It first runs straight inwards, almost transversely, and 

 then abruptly turning extends with a curve to the base of the 

 wing, this curved portion being more slender. On the upper or 

 back side of the wing this vein is pressed strongly downwards, 

 whereby a furrow is formed in the surface above it. On the 

 under side it stands out from the surface in bold relief, forming 

 an elevated ridge. Now it is this prominent ridge which is applied 

 to the inner edge of the opposite wing cover, and as it runs trans- 

 versely it will at once be seen that when the wing covers are 

 slightly spread apart and closed again, the motion will draw this 

 ridge up and down against the edge to which it is applied, pre 

 cisely like the bow of a violin playing upon the strings. This 

 vein may therefore appropriately be named the fiddle-bow, M. 

 Goureau the only one who has particularly described these parts 

 In the common cricket having given to it the corresponding French 

 term archet. But if this vein were smooth like the other veins 

 it obviously could produce no vibration. It would be like a 

 fiddle-bow when greased. On examining it therefore with a mag- 

 nifying glass in a strong light, an appearance like that of very fine 

 transverse lines may be discovered. And on being placed in a 

 microscope the real structure of this part may plainly be seen. 

 What at first appeared like fine transverse lines is found to be a 

 regular row of little flat cogs or teeth, resembling the front teeth 

 of man, but rather more broad than high and slightly narrowed 

 into a neck at their bases. They are inserted at short distances 

 apart, somewhat as the nails of the fingers appear when the end 

 of one finger is placed upon the top of another in a row. It is 

 but a short portion of the most projecting part of the vein tliat is 

 occupied by these teeth — little more than the twentieth of an inch 

 in length; and in tliat short distance twenty-one teeth are inserted, 

 with intervals between which are more than double the lengtli of 

 tlie teeth. The teeth do not stand perpendicular to tlie surface, 

 but incline towards the inner margin of the wing cover, and that 

 portion of the vein which is studded with them is about the tenth 

 of an incli from tlie inner edge. We shall now be able to under- 

 stand the cause of the several peculiarities in the stridulation of 

 this insect. It will readily be perceived that its fiddle-bow being 

 drawn against the edge of the opposite wing cover, and the teeth 



