1896. ] EXPEDITION ON THE LOWER AMAZON. 775 
and Locusts. It was, however, noticed that as we proceeded 
further up the river the number of insects that visited us by night 
sensibly diminished. The reason for this I am at a loss to 
understand ; but the same observation was made by Mr. Bernard 
Piffard, a naturalist who passed up the river about the same time 
as ourselves on board one of the boats of the Red Cross Line. 
Hymenoptera.— As regards this Order my best day’s collecting 
was at Obydos, where on Feb. 2nd I was fortunate in finding 
a large bush in full flower and covered with specimens of a great 
variety of species. At each locality visited the most conspicuous 
and commonest of the large Hymenoptera were various species of 
Pepsis, while the common Wasp of the Lower Amazon and the 
Para River was found to be Polistes canadensis, Linn. This species 
abounds everywhere, and numbers of its stalked nests are to 
be found attached to the rafters in every open shed or similar 
building : they were particularly noticeable inside a little mortuary 
chapel in the cemetery at Itacoatiara. Here and there on the 
Parana de Buyassu, as well as at Gurupd and other places, a long, 
white, cylindriform object was observed hanging to the branch of 
a tree; this was the nest of the Card-making Wasp (Chartergus 
chartarius, Oliv.). The natives are extremely fond of these nests 
as ornaments for their houses. Some of the Bees met with seemed 
particularly inquisitive creatures: thus in clearings in the forest 
Chrysantheda nitida, Perty, a small species of a brilliant metallic 
green, hovers around one, or over any article one may have thrown 
upon the ground, as if inspired with the utmost curiosity ; while, 
when steaming about in the ship’s launch at Buyassu, a large 
reddish-brown species of Hpicharis hummed round us in sweeping 
curves, and by its actions led us to mistake it for a Horse-fly 
(Tabanus). Among the various species of Ants the well-known 
Saiibas, or Leaf-carrying Ants (Atta spp.), were by far the most 
noticeable, and were abundant in the more open places everywhere. 
When collecting in a clearing one frequently came upon a narrow 
moving column of small green leaves, or rather segments of leaves, 
crossing one’s path and meandering away in either direction as 
far as the eye could trace it among the herbage, the insects them- 
selves often being entirely concealed by their burdens. 
Diptera were by no means so abundant as I had hoped, and the 
majority of the species met with were not very striking. The 
comparative scarcity of species of this Order must have been due 
to the season of the year, as I failed to come across numbers of 
fine species taken by Bates at the very localities we visited. Un- 
fortunately none of Bates’s Diptera in the collection of the British 
Museum are labelled with the date of capture. I am happy 
to say that I secured a fair series of specimens, representing 
a number of species, of the much-abused but rarely-collected 
Mosquito (Culear). Although in the forest Mosquitoes always made 
their presence felt, the only place where I found them really 
troublesome was Macapd; here they literally swarmed round me 
in clonds, and collecting quickly became a source of pain and grief. 
