488 Mr. Charles J. Galian 07i 



theoretical possibilities of the case would seem to allow, 

 they will probably show them to be a good deal removed 

 from the ordinary monotonous squeak produced by the 

 majority of stridulating Coleoptera. 



In addition to the genera mentioned above, stridulating 

 areas on the upperside of the head are found to be 

 present in species belonging to the following genera of 

 HisindcV : Wallacca, Botryono'pa, Oxycephala, Ccphcdodonta, 

 Prosopodonta and Hispa. They are absent in Arescus, 

 Ahtrnus and a few other genera, but taking the family as 

 a whole, they w^ill probably be found to occur in a 

 majority of the species, and as they seem to offer a 

 sufficient amount of variety in the details of their structure 

 they will probably prove to be useful as aids in the 

 diagnoses of species and sub-genera, if not of genera. 



In several genera of Coleoptera the striated area is 

 situated not on the upperside, but in a corresponding 

 podtion on the underside of the head, sound being pro- 

 duced by the friction of tJjis area against a small, inwardly 

 projecting ridge at the anterior edge of the prosternum. 

 A well-defined triangular or lenticular area marked with 

 very regular transverse striae is to be seen on the gula in 

 the Tenebrionid genus Praogcna and in the allied genera 

 Nesogcna, Dysgena and Lamprohotliris. Its presence in the 

 first-named genus was pointed out by me a few years ago, 

 but since then I have found that the irular stridulatino; 

 area is equally well-developed in many other Tcnchrionidx, 

 being in some cases characteristic of genera, in others 

 of small gi'oups of genera. It occurs in all the species I 

 have examined belonging to the genera Gonopus, Anoma- 

 lipus, Hopatr%nu8, Sclinus, Trigonopius, Pseudohlapis, Platy- 

 nutus and Eurynotus, and is to be found in several, but not 

 all of the species of Hdops. 



Its presence in Selinus affords a further means of dis- 

 tinguishing the species of that genus from those of 

 Dcndarus, to which they have sometimes a very close 

 resemblance. 



It occurs also in the genus Stcnerula, Fairm., of the 

 family Cistdidiv, and outside of the Heteromera, is met 

 with again under a slightly different form in the genera 

 Priohmm and DryopMlits of the family Ptinidie, and 

 Scolyt'us of the family Scolytidm. Its presence in Priohium 

 was scarcely to be expected, and is very interesting, in view 

 of the fact that some of the allied species of AiioUinx — 



