120 THE CAUSES WHICH PROPAGATE 



Intelligencer, after remarking- these insects usually creep from 

 their pupae shells at midnight, or later, adds : '' I have frequently 

 allowed one or the other to have a fly around the following- 

 morning'; they were soon satisfied, and would, Avhile uttering* 

 their squeaking" notes, hastily retire and settle in some dark- 

 part of the room/'' 



The Death's Head (Plate IV., Fig. 8), with its mimicry of the 

 macaws, like those screaming birds, lives well in confinement, but is 

 apt to die from gluttony. A number of individuals kept together 

 showed a disposition to pat one another with their fore-feet ; and 

 it has been shown that a touch of the delicate tarsus provokes a 

 squeak. So that, with our previous knowledge of this as a 

 weapon in courtship, we may infer that the sound of dread will 

 eventually appear the same timid and nervous note as other 

 instrumental music, and, no longer an echo of the menagerie 

 or harbinger of ill to the peasant of Brittany, will have to be 

 classed with the mysterious harpings that collect at the chimney- 

 stack, the shriek of the barn-owl at the hayrick, the chatter of 

 the bat at the eaves, or the baby cry of the hyaena. 



When we turn from the object to consider the organism 

 productive of the sound, we are able to deduce more satisfactory 

 conclusions ; for in addition to facilities for an examination of 

 the anatomy of the terrible Sphinx itself, we glean much from 

 the celebi'ated controversy in which Reaumur, 1742, Schroten, 

 1785, T. Vander Hoeven, 1859, support a proboscis-palpi theory ; 

 Roesel, 1755, Ghiliani, 1844, Wagner, 1836, a proboscis expira- 

 tion theory ; Lory and Nordman, 1838, the abdominal expiration 

 theory ; and Passerini, 1828, Westmaas, 1860, the Passerini 

 theory. The view here adopted will be intermediate between 

 the frictional and expiration theories. I will begin by quoting 

 the experiments of Landois in 1867, in confirmation of Reau- 

 mur, thus given in his little pamphlet on the '^ Ton und 

 Stimmappai-ate der Insecten''': — 



'^ On first impression the singular piping made led me to 

 think the note was produced by friction, because it has a resem- 

 blance to the note of many other insects which produce their 

 music in this way. I could not approach the note instrumentally. 

 One similarly finds it scarcely possible to reach the pitch of the 

 note of the Lonfficornes. 



