of Buprestidze and Elateride. 187 
as a separate piece a small part of the skeleton situated near the 
root of the coxe and called by him the trochantin, only very 
little attention was paid to it. The modern examinations of the 
external skeleton of insects, undertaken for the purpose of dis- 
covering useful marks of distinction for the numberless genera 
and other divisions established by entomologists according to a 
general impression of the habitus of the animals, have, however, 
in some cases led to the trochantins being taken into considera- 
tion ; and they are said to exist in some cases, but to be wanting 
in others. This view, however, appears to be erroneous. They 
seem never to be wanting im Coleoptera (to which we are now 
particularly alluding), although they vary very much in size and 
shape; and the difference in question would be more correctly 
indicated by describing the trochantins as either covered by a 
prolongation of those “plates of the skeleton which surround 
the coxa, or uncovered and bare. At the same time, however, 
eases would occur in which it might be difficult to say whether 
the trochantins should be called covered or uncovered, as in 
some instances they are not visible till the coxze are turned back 
in their sockets. Besides this, the definition of the family of 
Buprestide now generally adopted contains another still more 
misleading feature—that part of their thorax which has been 
called the trochantin being an entirely different piece and having 
nothing to do with the coxa. In one instance the common 
interpretation has been exchanged for a new one; but this new 
interpretation is not only erroneous in itself, but does not agree 
with a thorough understanding of the true structure of the pro- 
thorax in insects. 
In Buprestide, as well as in Elateride, each of the anterior 
coxe is on the outside surrounded partly by a receding pro- 
longation of the prosternum, and partly by a portion of the lower 
edge of the epimeron. In the first group of the family of Ela- 
teridze (see my classification below) these lateral laps of the pro- 
sternum are veryshort; but in the second group of Elateridzeandin 
Buprestidz they are so long that they occupy about the same space 
as the epimera on the outer margin of the coxa. In all Elateridze 
the laps of the prosternum aud the epimera join so-closely that the 
upper and outer part of the coxa, and with it the trochantin, are 
entirely hidden ; whilst in Buprestidae the parts in question do not 
join closely, whereby the socket of the coxa receives a small and 
narrow extension on the outside, and in this open groove a part 
of the coxa is always seen, whilst the little round trochantin 
itself is not seen, unless the coxa is turned back a little. It is 
therefore better to express the difference between these two 
families in this respect by drawing attention to the opening be- 
tween the prosternum and epimera than by saying that the 
