64 Studies on Arthropod a. I. 



Stridulating organs built according to the same principle 

 as in Penceopsis, Acanthocarpus, Palinuridcp, etc. are known in 

 males of European Aranese as Asagam and Steatoda and in nu- 

 merous Insects, thus in both sexes of Necrophoridae, in most 

 Cerambycidae, in the genus Crioccris (fam. Chrysomelidse) , in 

 several genera of lyamellicornia and in the larvae of at least most 

 types of that big family (the Lucanidae included), in some other 

 Coleoptera, in the Reduviidae (Hemiptera), etc. (The organs in 

 Cicadidae, lyocustidae etc. are omitted here) . In all the terrestrial 

 Arthropoda enumerated we find an .area, or two areas, with 

 regularly arranged and generally fine to extremely fine, trans- 

 verse ridges, and a sharp margin, a row of minute tubercles, 

 or the end of rostrum acts as bow. We generally know little 

 and frequently nothing on the biological role of the organ in 

 most of these Insects, but it must be emphasized that in every 

 form known to me the ridges on a stridulating are sim- 

 ilar as to thickness and distance; consequently one 

 might suppose that only a single tone could be produced, and 

 that modulation must be rather limited. But that is in reality 

 not always the case; for the best proof of the opposite, and the 

 most interesting obser\^ation on the use of stridulating organs 

 of the normal structure we are indebted to J. C. Scliiodte (Naturh. 

 Tidsskrift, 3. Raekke, B. VII, 1870, p. 188). Schiodte experi- 

 mented with specimens of Nccrophorus, especially A^ vespillo, 

 and writes: "When listening to a flower-pot in which several 

 specimens of Nccrophorus are about letting down a carcass [of 

 a small mammal or bird], one hears distinctly that they during 

 the work underground communicate mutually by the language 

 of stridulation. The sound is now higher and hasty, now deeper 

 and smoothered, and on the whole modulated in tlie most 

 manifold way. Sometimes a pause is suddenly interrupted by 

 a single sharp tone instantly answered by a similar one from 

 another specimen or simultaneously from se\'eral specimens. 



