On the Upper Berbice River. 321 



their absence, and but a few lizards had been observed 

 — notably, the common iguana (Iguana tuberculata). 



Insefts were considerably more numerous than other 

 forms. The bright blue Morpho menelaus, and the blue- 

 barred Morpho achilles were often seen flitting across 

 the river or among the trees by the banks, together 

 with the beautiful Urania leilus and the Papilio pro- 

 tesilaus and P. thoas, while the yellow butterflies 

 (Callidryas and other forms^ and the beautiful Heli- 

 conids were fairly common. Of Myriapods, a friendly 

 centipede (Scolopendra) had been caught while making 

 his way under my shirt for shelter, and a few beetles 

 had also been obtained at the various camping grounds. 



Though doubtless many interesting specimens were 

 obtainable in these lower parts, no systematic attempts 

 were made to procure them, the obje6t of the trip being 

 chiefly to explore and colle6l above the falls higher up. 

 The health of the party too had suffered somewhat while 

 passing through the lower swamps, and three of us had 

 already been prostrated with severe malarial fever, 

 though only of short duration. 



At Itabru there was a marked change in the chara6ter 

 of the surrounding country. The banks became high, and 

 rose upwards gradually into low hills, more especially 

 on the left bank where for several miles a sandstone 

 formation extends, evidently contemporaneous with that 

 on the Potaro at the Kaieteur falls. It attains its 

 highest point at Parish Peak, about 1,000 feet above the 

 sea-level, some few miles above the cataraft. 



The Itabru catara6t, a representation of which is given 

 in Schomburgk's *' Views in the Interior of Guiana," 

 is formed by a wide dyke of quartz-porphyry which crosses 



