334 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
ventral portion of the suture between the metathorax and abdomen to 
the postero-lateral portion of the metathorax. In the pupa (Plate 3, 
Figure 7, jlx. cox. m?thx. 5) this muscle has changed its position con- 
siderably, extending more nearly laterad from the newly forming meta- 
furca. Its origin in the zmago (Plate 5, Figure 11, jlz. cox. mt?the. 5) is 
on the anterior portion of the median lamina of the metafurca (m#’fur. 4). 
From this it extends laterad and a little caudad, attaching by a long ten- 
don to the suture between the metasternum and coxa, a little dorsal to 
the insertion of the muscle last described. 
Extensor coxae metathoracis primus. 
(Premier extenseur de la hanche of Straus-Diirckheim ; extensor tro- 
chanteris metathoracis of Luks.) 
This extensor is composed of a single fibre in the larva (Plate 1, 
Figure 4, ext. cox. m?thx. 1), whose origin is on the ventral portion of 
the suture between the metathorax and abdomen ; its insertion is on the 
postero-lateral surface of the upper part of the larval leg. In the pupa 
(Plate 3, Figure 7, ext. cox. m’thx. 1) its position has changed to some 
extent, as a result of the changes in position of both its attachments, Its 
origin in the zmago (Plate 5, Figure 11, ext. cor. mt’thx. 1) is on the 
posterior face of the lateral wing of the metafurca (m#?fur. 3), from which 
it extends ventrad and caudad to its insertion on the posterior median 
surface of the coxa. 
Extensor coxae metathoracis secundus. 
(Second extenseur de la hanche of Straus-Diirckheim ; extensor trochanteris 
metathoracis of Luks.) 
This muscle properly belongs to the first abdominal somite, but since 
it acts as an extensor of the coxa in some beetles, it is spoken of here 
among the muscles of the metathoracic leg. In the larva this muscle 
forms part of the ventral antero-posterior group of muscles of the first 
abdominal somite. During pupal life (Plate 3, Figure 7, eat. coz. 
mt'thx. 2) there is a great change in this group of muscles. Some de- 
generate, while the remainder metamorphose, to form this so-called 
extensor of the coxa, which in the zmago (Plate 5, Figure 11, ezt. cox. 
mt’thx. 2) is divided into two parts. The origin of these muscles is on 
the posterior side of the posterior lateral horn of the metafurea (m?’fur. 2) 
and their insertion, on the boundary between the first and second 
abdominal somites, very close to the median face of the metacoxa. 
