CftAP. I. SANDY BEACHES. 35 



and it did not, for some time occur to us to consult our 

 little companion, who had been playing with his bow 

 and arrow all the way whilst we were hunting, ap- 

 parently taking no note of the route. When asked, 

 however, he pointed out, in a moment, the right direc- 

 tion of our canoe. He could not explain how he knew ; 

 I believe he had noted the course we had taken almost 

 unconsciously : the sense of locality in his case seemed 

 instinctive. 



The Monedula signata is a good friend to travellers 

 in those parts of the Amazons which are infested with 

 the blood-thirsty Motuca. I first noticed its habit of 

 preying on this fly one day when we landed to make 

 our fire and dine on the borders of the forest adjoining 

 a sand-bank. The insect is as large as a hornet, and has 

 a most waspish appearance. I was rather startled when 

 one out of the flock which was hovering about us flew 

 straight at my face : it had espied a Motuca on my neck 

 and was thus pouncing upon it. It seizes the fly not 

 with its mandibles but with its fore and middle feet, and 

 carries it off tightly held to its breast. Wherever the 

 traveller lands on the Upper Amazons in the neigh- 

 bourhood of a sand-bank he is sure to be attended by 

 one or more of these useful vermin-killers. 



The bay of Mapiri was the limit of my day excur- 

 sions by the river-side to the west of Santarem. A 

 person may travel, however, on foot, as Indians fre- 

 quently do, in the dry season for fifty or sixty miles 

 along the broad clean sandy beaches of the Tapajos. 

 The only obstacles are the rivulets, most of which are 



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