286 TREUBIA VOL. II, 2—4. 
(page 105) mentioned in the foregoing, there is a record of the production 
in a marsh or a piece of flooded land in Mauritius, of 5062 individuals of the 
non-malaria-transmitter Myzorhynchus mauritianus DARUTY and d’EMMEREZ 
per 10.000 M? and per day. There being about as many males as females 
among these mosquitos (30 : 31), this production expressed in my manners 
only amounted to 2'/, Anopheline females per 10 M? and per night (or 
“per diem”). ROSS (3?) himself says about this production observed by him, 
which is absolutely dwarfed by the Anopheline production stated by us 
for the Batavia empangs: “This output seems to have been rather large, 
as when the net was placed in another position the yield was much 
smaller”. 
Mr. VAN BREEMEN and I could observe that part of the mosquitos 
produced by the empangs perishes immediately after having emerged 
when in July 1918 we went to the ponds to watch the mosquitos emerging 
at evening. At the same time we observed that at least at the hour of 
our visit to the ponds (6'/,—7'/, p. m.), many more mosquitos emerged 
one evening than an other, which for the rest tallies with the results yielded 
by our catches with mosquito-nets. 
The mosquito pupae which we saw disclose were in the thin layer 
of water spreading over the thick masses of plants chiefly consisting of 
Chaetomorpha and reaching up to just beneath the surface of the water. 
After the imagines had emerged they continued for a little while sitting 
on the empty pupa-skin and then flew away. Swarms of swifts, shortly 
afterwards yielding place to bats then flew about over the ponds evidently 
feasting upon the newly emerged mosquitos as they flew away. 
In the Netherlands East Indian literature on Myzomyia ludlowi THEOBALD 
one commonly finds it stated that the larva of this mosquito is chiefly 
found in salt water. Thus SWELLENGREBEL (#) says: “It” (scil. Myzomyia 
ludlowi THEOBALD) “generally prefers salt water”, to which he adds that 
according to CHRISTOPHERS the larvae of /udlowi live exclusively in salt 
water. Elsewhere SWELLENGREBEL says (°°) that the littoral breeding-places 
of /udlowi are mostly salt-water breeding places. In a third place the same 
author says (°7): “Along the coast /z7/lowi is mainly an inhabitant of salt 
water, though it is also found in fresher” (sic) “water near the sea”. 
MANGKUWINOTO (°*) has the following passage: “The larvae” (scil. of 
ludlowi) “1 only found along the coasts, principally in stagnant salt or 
brackish water containing water-plants, occasionally also in pieces of fresh 
water and unworked sawahs with stagnant water and water-plants, but 
usually in smaller numbers than were found in salt or brackish water”. 
Now it is a fact that in the littoral zone the /zdlowi larvae live chiefly 
in breeding-places containing salt or brackish water. I would however 
point out that it does not seem impossible to me, in connection with 
the results of Mr. VAN BREEMEN’s and my investigation, that it might 
not be the salt, but one or more other conditions realised in the littoral 
