276 



TSOPODA. 

 NORM ALT A 



Genus MGA. (Leach). 



Generic character. The three anterior pairs of legs in this 

 genus are strong and terminated by a powerful hook-like finger, 

 whilst the four posterior pairs are longer and more slender, 

 with a but slightly curved terminal finger, so as to fit them 

 for progression ; the short inner antennae have the basal joints 

 very broad and flattened, occupying the front margin of the 

 head. 



THE species of this genus are of large size. They 

 are oval, moderately convex, with most of the segments 

 marked transversely with a slight ridge. The coxae or 

 first joint of the legs (epimeral pieces of Milne Edwards) 

 are formed so as to appear as part of the dorsal surface. 

 The eyes are of large size and oval, extending consider- 

 ably backwards at the sides. 



The outer antennae are affixed beneath the fore margin 

 of the head, and are separated from each other by an ele- 

 vated scutcheon-like piece or labrum ; they are composed 

 of five or six strong basal joints gradually increasing in 

 length, but diminishing in thickness, and are terminated 

 by a flagellum composed of about a dozen articulations. 



The mandibles are strong, with the apical portion angu- 

 lated and bifid ; they are furnished with a prominent three- 

 jointed palpiform appendage arising near the external 

 base. The outer-foot jaws are rather valve-shaped, with 

 the basal joint strong and elongated, bearing a triangular 



