17(5 EVENINGS AT THE MICEOSCOPE. 



long slender roots, dilated at their bases ; — this is the 

 pair of viaxillce altered and modified into- a kind of 

 sheath for the mandibles. On each side projects an 

 elegant club, bristled with coarse black hair, and cov- 

 ered besides with a coat of very minute hairs ; these 

 clubs are the maxillary palpi. 



But now we come to the terminal part, consisting 

 of a pair of lobes, together forming a rounded triangle 

 in their outline. This is the dilated and thickened ter- 

 mination of the labium, and is the instrument by which 

 the liquids are so rapidly sucked up. It is impossible 

 to describe this beautiful structure intelligibly : and 

 indeed it is not well understood even by those who 

 have devoted their lives to this branch of natural 

 science. The principal feature apparent is a wide clear 

 membrane, through which run with admirable sym- 

 metry a series of tubes. These tubes consist of four 

 primary ones, all originating near the centre of the ex- 

 pansion, and radiating thence, two backward towards 

 the two lateral angles of the triangle, and the other two 

 nearly side by side towards its point. From each of 

 these, along its outer side only, branch oflf the minor 

 tubes, very numerous and close together, going otf in a 

 slightly sinuous line direct to the margin, diminishing 

 regularly in their course, and at their extremities curv- 

 ing over, so as to bring their open tips to the surface of 

 the skin. 



The construction of these tubes is highly interest- 

 ing : they are formed, like the air-pipes {trachea^, of a 

 multitude of horny rings ; but with this peculiarity, 

 that the rings do not form a continuous spiral, but are 

 separate and distinct ; and are moreover imperfect ; 

 for each wire (so to speak) does not perform a complete 



