274 [Dece?''^'-' / 



puzzled me for many years. In the huge Central American PassaV^to 

 of the genus ProcuJus, the elytra are completely soldered, and t"g3 

 insect has no powers of flight whatever, and yet the wings exist iiP a 

 strangely modified form ; they are long strips about an inch and a hilf 

 in length, and of a shape that is very rarely seen in insects. That an 

 insect should have wings of such a form has seemed to me remarkable 

 ever since I first observed the fact. On reading Mr. Babb's note, it 

 was at once suggested to me that here we have a case in which the 

 wings have entirely lost their function as organs of flight, but have 

 preserved their stridulation purposes ; and there can, I think, be no 

 doubt that this is correct. 'Jhe stridiilating area on the dorsum of the 

 abdomen is prominent in Proculus, and the wing-remnant is just of 

 the right length to rub the area, and, moreover, presents a special edge 

 at the tip of an effective character. This is a very interesting case of 

 change of function of an organ. Wings are organs of flight. In 

 PassalidcB generally they are organs of flight and stridulatory organs; 

 in Proculus they are stridulatory organs, but are not at all organs 

 of flight. 



Coupling this discovery as to the stridulating organs of the imago 

 with Schiddte's and my own previous demonstration of sound-producing 

 organs in the larva, and with Ohaus's charming discovery as to the 

 parental functions of these beetles, we find a pleasing little entomo- 

 logical family history is disclosed. The creatures live in rotten wood. 

 The parents do not die before the young are hatched, as is generally 

 the case in the insect world, but survive and live a family-life in the 

 logs. The young are from two to seven in number, and the parents 

 tear up the wood for the young, these, according to Ohaus, being 

 unable to live without the parental assistance. The value of stridu- 

 lating organs under these circumstances is clear. We can translate 

 the Passalus proceedings into their human equivalents very easily. 

 A grub is hungry and makes movements of impatience giving rise to 

 sounds ; the parent tears up some wood for it, and while doing so 

 stridulates, as if to say, " Coming, grub, but do not be impatient." 



The recent revelations made by Fabre and Ohaus as to the natural 

 history of Lamellicorns will, 1 think, be found to justify our treating 

 these insects as the highest of the Coleoptem. Ethology, Esthetics, 

 and Anatomy, are found to coincide in support of this view. 



Cambridge : 



November, 1904. 



