INSECT VARIETY. 105 



couventioual scales. Certain passages in the recitative of crickets 

 evidently correspond with our intervals : but the greater portion 

 of all such music is much too rapid, and it is also so uncertain 

 when the performers may stop, that we cannot extemporise any 

 musical bar whatsoever. Then the pitch is rarely attainable by 

 our shrillest and harshest instruments, and the intervals employed 

 are so minute that they differ greatly from the gross periods into 

 which we divide the octave. The eccentric development of the 

 musical phenomena on European areas, no less than the irregular 

 distribution of species, speaks of forms extinct or of outlying 

 groups. 



STllIDULATION OF THE NEUROPTERA. 



The stridulation of the Neuroptera has been inferred from 

 the probability of an extinct insect found by Dr. Scudder in the 

 Devonian strata of New Brunswick, being musical and apper- 

 taining to this order, and on the story of the beating, presumably 

 stridulation, at Upminster, of a louse-like insect identified as the 

 Museum pest, Afropo.s pnlmtorins. The latter is stated to tick 

 for hours together on paper like an antique pocket- watch, with 

 sudden shakes of the body ; to answer its pulsations artificially 

 produced ; and after a fortnight thus to pair with the female. I 

 find no subsequent confirmation. 



STRIDULATION OF THE HYMENOPTERA. 



If, with Goureau, we consider the sound given out by 

 the Sand-wasps to be vocal, we shall have only the Formi- 

 cidse to treat as stridulators among the bee tribe. And apart 

 from the hissing of questionable origin given out at times by 

 ant-streams, the solitary species of the parasitical genus Mat ill a 

 have been long known to possess the power of producing a shrill 

 frictional cry, sibilant in tone, and common to the winged male 

 (Plate III., Fig. 9cJ) and wingless female (Fig. 99). This 

 sound Goureau considers perceptibly due to their rubbing a 

 shining surface on the third abdominal segment beneath the 

 inner border of the much-elongated second segment (Plate VI., 

 Fig. 8, a) ; and in this he is corroborated by Herr N. West- 

 ring, who remarks this shining surface is a little flat dark shield, 

 which, as seen beneath the glass, is transversely and finely rugose 

 (Fig 8,0- 



