INSECT VARIETY. 191 



talc-like spot; and the same g-entleman, in a subsequent com- 

 munication to the Entomological Society, considers certain 

 of the Mantida,^ or Leaf Insects, stridulate by rubbing 

 the abdomen against the lamellar expansions at the anterior 

 margins of the wing-covers, which, when the latter are in 

 repose, are inflexed beneath it. These extensions are in both 

 sexes converted along a greater or lesser portion of their length 

 into highly indurated, erect, and obtuse teeth, which, being 

 furnished with lateral setae, appear morphologically identical 

 with the microscopically small, blunt serratures seen in a 

 Malayan kind. He also stated he was informed a certain 

 Indian Leaf Insect, when tormented, kept making a " hissing 

 noise, ^■' without obvious movement of the alar organs — a notion 

 previously, though seemingly incorrectly, advanced in respect of 

 the common European Preying Mantis, by Colonel Goureau, who 

 says that when this species is alarmed on a tree, it places itself in 

 an attitude of defence, and rubs the sides of the abdomen against 

 the interior borders of the wings and elytra, so as to produce a 

 noise like that of pieces of parchment rubbed together. 



CUESORIA. 



Individuals of a West Indian cockroach, nicknamed the 

 Drummer, and identified lately as Panchlora Maderce, F., are 

 frequently mentioned in books of the eighteenth century, as 

 responding from wooden structures in houses or in trading 

 vessels, with a reiterated drumming or knocking. This noc- 

 turnal sound, likened by the Rev. J. A. Marshall to the "chur^^ 

 of a very distant nightjar, is said not to be produced by the 

 species when in confinement, or when they find themselves 

 observed, fear then serving as a check on its emission. 



The stridulation of spiders and crabs is similar in production, 

 and appears to fulfil the same ends as in insects. The first 

 crepitate from fear or anger. Westring artificially discovered 

 that several poisonous black spiders decorated with blood-red 

 spots,t found in the vineyards of Southern Europe and else- 

 where, have the power of making a very feeble sound, while 

 their females are mute. This they effect by means of a serrated 



* Empusidce. 



f Thcridon (Asciffena, Lund) serratipcs, quadri-jmnctatum, guttatu7n. 



