BREED: METAMORPHOSIS OF THE MUSCLES OF A BEETLE. 333 
The remaining muscles of the lateral dorso-ventral group are all leg 
muscles, either flexors or extensors. The homologies with the muscles 
of Dytiscus are not all entirely certain, because the leg muscles of Dy- 
tiscus are so different from those of Melolontha and Thymalus, that 
the homologies are not always evident. 
Flexor coxae metathoracis primus. 
(Premier fléchisseur de la hanche of Straus-Diirckheim; extensor trochan- 
teris metathoracis of Luks.) 
This muscle is found in the larva (Plate 1, Figure 4, flz. cox. mt’thx. 1) 
as one fibre, whose origin is on the ventral portion of the suture between 
the metathorax and the abdomen, and whose insertion is on the outside 
surface of the leg on a portion which later forms the coxa of the adult. 
In the pupa (Plate 3, Figure 7, flz. cox. mtthx. 1) its position is changed 
greatly by the formation of the metafurca, and the shifting of the leg 
posteriorly. The origin of this muscle in the imago (Plate 5, Figure 11, 
fix. cox. mt?'thx. 1) is on the posterior part of the median lamina of the 
metafurca (m#’fur. 4), and its insertion, on the anterior ventral edge of 
the coxa about one third of the distance from the trochanter to the 
lateral edge of the coxa. 
For an account of Flexor coxae metathoracis secundus, see page 325, and 
for an account of Flexor coxae metathoracis tertius, see page 326. 
Flexor coxae metathoracis quattuor. 
(Quatriéme fléchisseur de la hanche of Straus-Diirckheim ; flexor alae 
metathoracis of Luks.) 
This is the second muscle of the imaginal metathorax which has not 
been found in the larva. It is found in younger pupae than is the first 
muscle (musculus episternalis), but it is probably a muscle of new forma- 
tion in the pupa (Plate 2, Figure 5, flx. cox. mt’thz. 4). In the imago 
(Plate 4, Figure 9, flx. cox. mt’tha. 4) it takes its origin near the middle 
of the dorsal side of the episternum, and, extending caudad and a little 
ventrad, is inserted on the extreme anterior lateral edge of the coxa. 
This is the muscle which Luks has incorrectly described for Dytiscus as 
the flexor of the wing. 
Flexor coxae metathoracis quintus. 
(Cinquiéme fléchisseur de la hanche of Straus-Diirckheim ; musculus 
Furcae dorsalis of Luks.) 
The fifth metathoracic flexor of the coxa is found in the Jarva (Plate 1, 
Figure 4, flx. cow. mt’thx. 5) as a single fibre, extending from the latero- 
