712 Mr. Gilbert J. Arrow ooi 



concerning an insect which has for ages attracted attention, 

 I cannot help thinking that this witness must have made 

 a rather too free use of his imagination. No one probably 

 has made more study of these insects in their natural en- 

 vironment than the French naturalist Fabre, but, from his 

 very detailed account of it, it is evident that he never 

 heard it utter any sound. More than this, he took special 

 pains to ascertain whether there was any co-operation 

 between male and female and pronounced decidedly 

 against it, having found that when two beetles seemed 

 to be working in conjunction they were as often as not 

 of the same sex.* Professor Flinders Petrie and others 

 who have frequently watched and handled them inform 

 me that they have never heard any sound from these 

 beetles. 



It has been questioned whether the tuberculated area 

 on the mandible of the larva in this and other groups of 

 Lamellicorns is really a sound-producing organ, but tliis 

 point seems to be set at rest by actual observation in other 

 larvse in which an exactly analogous structure occurs. A 

 finely-tuberculated area at the base of the mandible, with 

 corresponding teeth upon the maxilla, have been described 

 by Schiodte in larvse representing the families Copridae, 

 Aphodiida3 and Melolonthidoe, but in three other families 

 (Rutelidae, Dynastidse and Cetoniidoe) a similar but rather 

 more elaborated form of the same arrangement appears. 

 Dr. Ohaus, who has recently made many extremely 

 interesting observations upon the habits of Brazilian 

 Lamellicornia, has described the stridulation of the 

 larval Macixispis cincta, one of the Rutelidse."!" I have 

 examined the apparatus of an allied species, M. tristis, 

 from Dominica, and it also occurs in the other genera 

 of which the larvse have been examined {Pelidnota, 

 Parastasia, etc.), and very likely throughout the family. 

 In these larvae each mandible bears an oval, rather concave, 

 area, little larger than a pin's head, upon which the 

 tubercles found in the same situation in the Melolonthidse 

 are replaced by transverse ridges so fine that fifty or more 

 are compressed into this small space. Upon the basal 

 part of the maxilla, where it comes into contact with this 

 instrument, is placed a row of sharp but stout, only 

 slightly-elevated teeth. By scraping these upon the 



* Fabre : Souvenirs Entomologiques, 1879, p. 10. 

 t Stett. Eut. Zeits., 1899, p. 237. 



