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 jtupa (Plate 3, 

 Figure 7, Jix. cox. nd'thx. 5) this muscle has changed its position con- 

 siderably, extending more nearly laterad from the newly forming nieta- 

 furca. Its origin in the imago (Plato 5, Figure W, fix. cox. mt'thx. 5) is 

 on the anterior portion of the median lamina of the metafurca (mffur. 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 metathoracw primus. 



{Premier extenseur de la hancke 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. mt'thx. 1), whose origin is on tlio 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, ejii. cox. mt'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 imago (Plate 5, Figure 11, ext. cox. mt'thx. i) is on the 

 posterior face of the lateral wing of the metafurca (mt'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, ext. cox. 

 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 imago (Plate 5, Figure 11, ext. cox. 

 mVtlix. 2) is divided into two parts. The origin of these muscles is on 

 the posterior side of the posterior lateral horn of the metafurca (int'fur. Si) 

 and their insertion, on the boundary between the first and second 

 abdominal somites, very close to the median face of the metacoxa. 



