PHOTINUS. 45 
and sixth segments and apex entirely clear yellow and smooth. The two subapical 
ventral plates are notched triangularly in their centre; the seventh very short, only just 
visible. 
The female has the same abdominal plates yellow, the structure being as usual in 
this genus, the two subapical being emarginate, and the apical (seventh) plate notched. 
19. Photinus sanguinicollis. (Tab. III. fig. 8.) 
Photinus sanguinicollis, Gorh. Trans. Ent. Soc. 1880, p. 30. 
Hab. Costa Rica, Irazu (Rogers). 
The specimen figured is a female, and at present remains unique. I have only seen 
one other specimen, which may possibly belong to the same species, but which differs 
from it both in having the sides of the thorax more widely fuscous, and also in having 
the abdomen wholly black. This specimen is from Vera Paz, Cubilguitz. 
In the present state of our knowledge of these most interesting insects it would be 
absolutely impossible to decide upon their identity or otherwise on single specimens from 
different localities. When they are inuch more fully known it is probable that long 
series of closely allied species will be found. I am also inclined to think the same 
species may present a luminous and a non-luminous form at different times, or under 
varying circumstances. 
20. Photinus aurora. (Tab. III. fig. 7.) 
Photinus aurora, Gorh. loc. cit. p. 30. 
Hab. Costa Rica, Irazu, Rio Sucio (Rogers). 
21. Photinus cordove. 
Nigro-fumosus, subopacus, thorace flavo, disco miniato, in medio et ad basin infuscato, antennis compressis. 
Long. 9-10 millim. ¢ 9. 
Hab. Mexico, Corduva (Sallé). 
Very similar in size and general appearance to P. ruficollis. It is distinguished, 
however, by permanent characters. The thorax has the disk with a dark vitta widening 
at the base; even its whole edge is sometimes slightly infuscate. The scutellum is 
black, as well as the whole of the abdomen—it being therefore doubtful whether this 
species is capable of emitting light. 
In paler examples the front femora and central parts of the sterna are pitchy. 
The only species with which this could be confounded is P. fumigatus. It is, how- 
ever, much larger and wider, and has the thorax brighter red, with only a narrow and 
rather indistinctly fuscous vitta. 
