410 ANNI7AL REPORT OF NEW-YOITK 



GRAPE. LEAVES. 



with which it is furnished grating thereon will cause such a jar 

 in tlie sash or frame work of both wing covers as will impart a 

 brisk vibration to all the little tabrets or membranous cells which 

 are placed in this frame work. And the shrillness of the note of 

 this insect is due to the extreme thinness of the membranes and 

 tlie violent vibrations into which they are thrown by the sharp 

 grating w^hich these projecting teeth of the fiddle-bow with the 

 little intervals between them produce. As the teeth incline 

 inwards they act only when the wdng covers are shutting together; 

 when they are opening apart no grating can occur. It hence 

 results from this peculiar mechanism that as the wing covers 

 are successively opened and closed, notes and intervals of about 

 equal length are alternately produced. The row of teeth more- 

 over being so short, they can cause a vibration of only a moment's 

 duration, and it is not in the power of the insect to produce a 

 continuous sound or a prolonged note. The reason of the several 

 differences between the song of this and of the common cricket, 

 whose stridulation has been described wdth so much exactness by 

 M. Goureau (Annals Soc. Ent. vol. vi, p. 34) are all -readily 

 explained by the differences wiiich we find in the structure of the 

 wing covers in these tw^o insects. In the common crickets both of 

 Europe and of this country, the fiddle-bow instead of projecting teeth 

 is merely furnished wath elevated transverse ridges or ribs, 

 and these occupy its whole length. Hence its note is more pro- 

 longed and far less loud and shrill than that of the flower cricket. 

 M. Goureau was able in the dead insect to so move its wing covers 

 whilst they were still pliant, as to produce the same sound which 

 it utters when alive; and by merely scratching with a pin upon 

 the fiddle-bow he found this sound w^as produced, though more 

 feeble, as but one wing cover w^as hereby vibrated. 



The White flower cricket measures about 50 to the tip of its abdomen 

 and its total length is about 0.70. It is of a milk-white color, sometimes with 

 a slight tinge of green. The tips of its feelers and of its feet are tawnj yel- 

 lowish and there is commonly a spot of the same color upon the top of its 

 head, which is oblong and broader at its hind part, commencing between the 

 bases of the antennae and extending back to a line with the hind side of the 

 eyes. The eyes in the living insect are of the same white color with the body, 

 but after death change to a brownish clay color, though in some specimens 

 they remain white. Upon the under side of each of the two first joints of the 

 antennae is a black dot, which is sometimes lengthened into a slender stripe or 



