440 Mr. F. Smith 07i the Genus Eulema. 



In examining minute objects, it is very desirable to acquire 

 the power of holding a lens with the eye after the manner of 

 a watchmaker ; this, besides giving as it were a third hand, 

 enables the operator, by means of a very high power, to pick 

 out objects from material spread over the slide, through the 

 aid of a subjacent mirror or black ground, and thus turn them 

 over and over so as to obtain a view, under a compound power, 

 of all parts of the object, such as it might be difficult, if not 

 impossible, to get under any other circumstances. 



Again, the microscopist should also endeavour, when he has 

 got the focus of the " line adjustment," to render it still finer 

 by gently pressing down the tube, whose resiliency, up and 

 down, will thus give the observer a better idea of a minute 

 object than any other means. Indeed it is absolutely neces- 

 sary with very minute objects. 



LXI. — A Revision of the Oenera Epicharis,'Centris, Eulema, 

 a7id Euglossa, belonging to the Family Apida3, Section Sco- 

 pulipedes. By Feederick Smith, Assistant in the Zoolo- 

 gical Department of the British Museum. 



[Concluded from p. 373.] 



Section Corbiculipedes. 



Genus Eulema, St.-Farg. 



Generic Characters. 



Head narrower than the thorax ; the clypeus produced an- 

 teriorly ; the labrum subquadrate, convex, its anterior margin 

 slightly curved ; mandibles subdentate, having on their inner 

 margin three blunt teeth ; the tongue elongate, nearly as long as 

 the body: the maxillary palpi two-jointed, the first joint shorter 

 than the second, its apex truncate ; the second joint twice the 

 length of the basal one, pear-shaped, and with a long stiff 

 bristle near its apex : the labial palpi elongate, setiform, two- 

 jointed, the division of the joints obscure. Thorax : wings 

 with one elongate marginal cell and three submarginal cells, 

 the first and second of nearly equal length, the third as long 

 as the first and second united ; the first recurrent nervure re- 

 ceived by the second submarginal cell near its apex, the 

 second recurrent uniting with the third transverse nervui'e. 

 The posterior tibise of the females much flattened, concave ex- 

 teriorly : in the male the tibise are convex, and concave above, 

 two thirds of their length from their apex towards their base. 



