CVIII 
sending me such as I wished, and as the resuit of his kindness 1 
hâve been able to make the following notes. 
In the position examples are found in after death, and in which 
they are represented in the figures that hâve been published, the 
head is extremely defiexed so that its anterior parts are placed 
beneath the thorax, and the front of the mandibles is directed 
beneath the insect to the posterior part of the body. In this position 
the peculiar posterior angles of the vertex rest upon the anterior 
edge of the pronotum just at its front angles, and the head hasa 
peculiar rigidity and immobility being deprived of ail capacity of 
rotation or nutation. This position is not, however, that in which 
the insect is found when alive and active, but is in fact a position 
of contraction' such as is assumed by many insects when they 
wish to protect themselves by inactivity during life, and which 
they usually assume at death. And actually the head of this insect 
possesses an extreme capacity of movement, for it will be found 
on thoroughly softening an example, and then overcoming the 
résistance of the powerful muscles by which the contraction is 
during life efiected and maintained, the head is raised to a quite 
horizontal position, and the posterior part of the vertex becomes 
immersed in the thorax, as far as the peculiar curved dépréssion ; 
the front wall of the dépréssion is then exactly applied to the 
front margin of the thorax to which it is exactly adapted : the 
head has thus a power of movement of nutation extending to about 
half the circumference of a circle. When the head is thus repla-. 
ced in its natural position, a most extraordinary peculiarity is 
discerned by inspection of the undersurface, where there exists, 
atthe back of the head and front of the prosternum, a large mem- 
branous space, the posterior boundary of which is the peculiarlv 
emarginate anterior edge of the prosternum; and it is alsoto be 
noted that this emargination is hispid, the middle (or hind portion) 
of the notch being very densely so, and the posterior portion of 
the membrane is also setose. 
The prothorax is also capable of great mobility at its junction 
withthe after body, and when it is extended completely covers the 
declivous space seen, in dried specimens, at the base of the wing- 
cases, leaving only the tip of the scutellum exposed. 
When the insect is placed in the position described, the plane of 
the thorax is on the same horizon as that of the wing-cases, and 
the head is slightly higher, its mandibles are advanced in front 
and are directed only slightly downwards, while the large and 
powerful gênai processes are directed vertically downwards. In 
this position the imbécile and apparently purposeless appearance 
of Hypocephalus as ordinarly seen has entirely disappeared, 
