54 



shaped ball, adapted accurately to a socket in the second joint, and 

 has projecting from either side of its base a sharp spine or trochanter, 

 for the insertion of the tendons of the abductor and adductor mus- 

 cles by which its movements are effected. The second joint (fig. 8, 

 b) bears the socket to which the ball of the first is adapted, and at its 

 opposite extremity is united to the third and principal portion of the 

 jaws, (fig. 8 c), which consists of a broad expanded corneous plate, 

 of less density than the preceding, and resembling in form and office 

 a similar structure well known as occupying the centre of the large 

 claw of the lobster, being for the attachment of the muscles by which 

 the mandibular hooks are moved to and fro. The whole mandibular 

 apparatus measures about the ^ of an inch in length, and, being very 

 firm and solid, presents a remarkable contrast in texture to the sur- 

 rounding soft parts w r ith which it is connected, and from which it is 

 easily detached. 



If the body of the insect be laid open the alimentary canal is seen 

 to be of considerable length, and much convoluted, (figs. 9 & 10). 

 It commences by an exceedingly delicate hair-like oesophagus, (fig. 7, 

 b), so narrow that it would appear to be specially destined to transmit 

 fluid nourishment, and nothing else. This terminates about the third 

 segment of the body in a minute globular cavity or proventriculus, 

 (fig. 7, 6-), which is of the same diameter as the rest of the alimentary 

 canal, and immediately below which four very short salivary vessels 

 enter, (fig. 7, d d d d). From this point commences the large intesti- 

 niform stomach, (fig. 10, a a), which after contracting in its first third 

 to the finest thread, (fig. 10, 5), again dilates and proceeds of uniform 

 diameter to the point where the four slender biliary vessels enter, (fig. 

 10, c), w r here it again contracts and forms a short intestine. The 

 whole alimentary canal is about six times the length of the body, 

 and of this length the stomach forms about five-sixths. Its greatest 

 diameter does not exceed one-third of a line, and its least is that of a 

 mere thread. The whole structure appears to be that of an animal 

 adapted to live on fluid nourishment. 



The principal external openings to the tracheae appear to be two 

 apertures situated on the dorsum of the last segment of the body, 

 and which constitute the last pair of the series of dorsal eminences 

 formerly noticed. These apertures correspond with the very remark- 

 able and conspicuous pair of organs occupying a similar situation in 

 the last segment of the oestrus of the sheep, and which are also the 

 external openings of the respiratory apparatus in that insect. 



None of the insects were alive when they came into my possession, 



