173 Pro 



Proalae. — Tlie anterior or fore wings, arising from 

 the sides of tlie mesothorax ; they vary greatly 

 in composition, covering and form. (L. fro, 

 and ala, a wing.) 



Proboscis. — A suctorial instrument for conveying 

 food to the mouth. (L. 'proboscis, a snout.) 



Proboscis. — The oral instrument of Diptera, in 

 which the ordinary trophi are replaced by an 

 articulated sheath,' terminated by the labella, 

 and containing one or more scapella covered by 

 a valve. (L. ) 



Procephalic lobes. — (Embryol.) The two flaps 

 formed by the first segments of the embryo, 

 dividing ; the segments being formed by the 

 primitive streak dividing by transversely im- 

 pressed lines into segments. (L. fro, and Gr. 

 Jcephale, the head.) 



Procerebral bridge. — A band uniting the two 

 halves of the brain. (L. fro, and cerebrum.) 



Procerebral lobes. — The two fused nerve lobes of 

 the procerebrum. 



Procerebral mass. — The mass of nerve centres, 

 nerves, andganglia constituting the procerebrum, 

 they are : the procerebral lobes ; optic ganglia ; 

 postretinal fibres ; ganglionic plate ; external 

 chiasma ; external medullary mass ; internal 

 chiasma ; internal medullary mass ; mushroom 

 bodies; procerebral bridge, and the central 

 body. 



