LOUSE. 
451 
fastened or agglutinated by its smaller end to the 
hair on which it is deposited. From this egg 
proceeds the insect, complete in all its parts, and 
differing only from the parent animal in its smaller 
size. Such diminutive specimens are far prefer- 
able, for microscopic observation, to the full-grown 
insects, shewing in a more distinct manner the 
disposition of the viscera, muscles, &c. &c. When 
thus examined by the microscope, the principal 
appearances are as follow: viz. the trunk or pro- 
boscis, which is generally concealed in its sheath 
or tube, is of a very sharp form, and is furnished, 
towards its upper part, with a few reversed aculei 
or prickles: the eyes are large, smooth, and black: 
the stomach and intestines, which possess the 
greater part of the abdominal cavity, afford an 
extremely distinct and curious view of the peri- 
staltic motion ; whilethe ramifications of the tracheae 
or respiratory tubes appear dispersed in an ele- 
gant manner throughout various parts of the ani- 
mal, and are particularly observable towards their 
orifices on the sides of the abdomen: the legs are 
each terminated by a double claw, not greatly 
unlike that of a lobster, but of a much sharper 
form ; and the whole animal is every where covered 
by a strong, granulated skin*. It is affirmed by 
* The magnificent figure of this animal by the ingenious Dr. 
Hook, engraved in his Micrographia, is well known to all who have 
attended to the minuter branches of Natural History. It is ob- 
served however by Leewenhoek tliat it is faulty in one particular; 
the antennie being represented as consisting of four joints only,, 
instead of five. 
