so7nc Luminous Coleaptera from Ceylon. 719 



the first which is narrowed in front. Posterior segment 

 truncately rounded. Photogenic organ roundly quadrate, 

 ahnost completely occupying the venter of the penulti- 

 mate segment ; emittii)g an intense greenish-yellow light. 

 Colour brownish ochreous, the basal half of each dorsal 

 segment dark brown. 



Length 30 mm. Breadth 7 mm. 



Although, in the example under observation, the light 

 was confined to the area of the large photogenic organ, 

 two examples of what appear to be the same species, from 

 Kandy , were reported by the collector to have exhibited — 

 when freshly caught — a supplementary series of luminous 

 points along each side. He describes them as being situ- 

 ated intersegmentally, and states that there Avere two 

 luminous points (one dorsad, the other ventrad to the 

 lateral line) at each junction of the segments. He did 

 not count the number, but thinks that the series extended 

 along the whole length of the abdomen. When I received 

 them, the insects were more or less moribund, and displayed 

 light from the terminal ventral organ only. Some eggs 

 laid by these examples did not exhibit any luminescence, 



Lampro2Jliorv.s tenebrosus, Walk. 



The males of this species, though ordinarily exhibiting 

 a very brilliant light, invariably approach a " calling " 

 female with their light shut off. I have frequently 

 observed the advent of the male, when watching a female 

 that was displaying its signal. The first intimation of the 

 arrival of the other sex is the partial eclipse of the 

 luminous discs of the female. Several males are often in 

 attendance upon a single female. 



The male of this species apparently seeks the female 

 solely by sight, for I have found them visiting females of 

 other species, including that of what I now know to be 

 Dioptoma. They are also constantly attracted to lamps at 

 night. 



Explanation of Plate LXXXVI. 



Fig. \. Harmatella bilinea, Walk, (diagrammatic) x 13 (p. 717). 

 2. Dioptoma adamsi, Pasc. ( ,, ) x 10 (p. 718), 



