structure of the LampyridcB. 65 



Luclola. Here both sexes fly, both are luminous, and 

 both have hxrgely developed po^Yerful eyes. 



Neither of these sections, however, comprise those 

 species which arc generally regarded as most typical of the 

 family, the largest, and those which appear on the whole to 

 have all their parts most highly specialised, and which, 

 therefore, we place at the head of a systematic list, such as 

 the genera Lamprocera and Cladodes. It is rather re- 

 markable that in these genera the light-emitting faculty 

 has not been developed in the same proportion as the rest 

 of the organs have, and that while one of these, viz., the 

 eyes, are also reduced in a direct ratio with the light, and 

 are small and uniform in both sexes, another organ, the 

 antennse, is developed in inverse ratio as the phos- 

 phorescence is diminished. I do not here speak of mere 

 length, or redundancy in the number of joints, which are 

 more usual in very simple and primitive forms of the 

 organ, such as we see in Blaita, but of a high degree of 

 specialisation, testified by large lamellar plates, or pectina- 

 tion. Whether the eye is developed at the expense of the 

 antenna, and is so to speak the receptacle of all the vital 

 forces of the head, or whether the antenna supplements 

 the loss of the other organ of sense, and is useful in 

 detecting the presence of the female, I only see one fact in 

 evidence, which is that this plumosity of the antenna3, in 

 one case, and this enormous development of the eye in the 

 other, are usually sexual characters predominating in the 

 male, but sometimes found in both sexes. 



I now offer some evidence in support of my view. The 

 species I have selected to illustrate the subject I have 

 arranged in three groups. 



i. Species with plumose antennae, small or moderate 

 eyes, both sexes winged, light-emitting surface confined to 

 one or more small spots. Genera exhibited Lamprocera, — 

 L. Latreillei S ? • The male only is luminous, and 

 apparently only slightly so. Cladodes, — C. lamellicoi'ms. 

 C. plwnosa, Gorh. The sexes are as yet undistinguish- 

 able. Vesta, — V. saturnalis, Gorh. Lucidota, — L. 

 flahellicornis, Phcenolis, — P. phimosa, Gorh. Mega- 

 lophthahnus, M. Guatemalce, Gorh. Of this genus it is 

 noticeable that Lacordaire remarks the name is unfor- 

 tunate, as the eyes are not larger than is usual in this 

 family. 



ii. Species in which both sexes are winged ; light 

 V 2 



