292 
Psyche 
[December 
(pl 2 ). The first visible pleurite in this case then is wholly formed 
of the third segment. 
On the other hand an elater (Fig. 1, B) shows clear evi- 
dence of the fusion commonly assumed. The second pleurite is 
very small (pl 2 ), but lies completely flush with the surface of the 
body and forms the actual articular surface facing the mete- 
pimeron. The suture is traceable dorsally, and continuous with 
the well marked fold between the second and third dorsal seg- 
ments, but it soon becomes ambiguous, and I am not sure I have 
indicated its course correctly. 
The obvious conclusion from this is that the loss of the 
second pleurite has taken place twice independently (at least), 
and that its absence is not necessarily an indication of a homo- 
geneous series of “higher Coleoptera.” In fact the presence of 
forms with a well marked second pleurite is known in both 
series (Omethes, for instance in the Serricorns besides the possibly 
degenerate Lampyridse; the early Dascyllidae in the Bostry- 
chiform series). 
Incidentally it appeared in this work that the common 
statements as to the number of free segments of the abdomen 
are not correct. In the elater only the last segment is free, 
while in Trypopitys the entire abdomen is ankylosed, even the 
sutures being obliterated, except the first. This is correctly 
stated in the descriptions of the genus, but not allowed for in 
any key I have seen. 
