176 MOSQUITOES OF NORTH AMERICA 
spiders are among the most important enemies of mosquitoes. Spiders are very 
abundant in these swamps and Doctor Leon states that enormous numbers of 
mosquitoes are caught in their nets and killed. Different species of spiders 
weave their webs on sedges, reeds and willows and it is not rare to find as many as 
twenty webs on one willow. Sometimes the number of webs is so great that they 
become continuous and completely enwrap the tree and one can conceive the 
large numbers of mosquitoes that can be caught in such webs. 
Mr. W. L. McAtee recently made an observation in Arkansas which is at 
variance with those already given and which indicates the necessity for more 
careful observations. 
“On a rainy day a large number of Anopheles quadrimaculatus were found 
sitting on a spider web in a hollow tree. Thinking they must be at least slightly 
entangled, I counted on capturing them easily. Upon putting my cyanide bottle 
near one, the whole swarm rose lightly on the wing, not sticking to the web at 
all. By further tests I found that they were perfectly at home on the web.” 
OTHER ARTHROPODS. 
Doctor Dupree once stated in a letter that he was satisfied that small crayfish 
and fresh-water shrimps kill the larve of mosquitoes. Britton has shown that 
salt-water shrimps (species not mentioned) will eat the larve of the salt-marsh 
mosquitoes but thinks that their structure and small capacity prevent them from 
consuming any great numbers. 
BATRACHIANS. 
It appears from the observations and experiments of Galli-Valerio and Rochaz 
de Jongh that frogs and toads will not capture mosquito larve or pupa. No 
observations appear to have been made with reference to frogs and toads as de- 
stroyers of adult mosquitoes but there can be no doubt that they capture mos- 
quitoes along with other insects. The above-mentioned observers found that the 
north African Discoglossus pictus, a frog-like batrachian, is an efficient de- 
stroyer of mosquito larve. This animal has the habit of capturing its prey under 
water while the frogs and toads do not do so. The same observers found that in 
Switzerland Triton cristatus and Triton alpestris are effective destroyers of 
mosquito larve. They observed that a certain puddle which in past years was 
inhabited by Triton cristatus at that time contained no mosquito larve ; during 
two subsequent years, when the tritons were absent, this same puddle harbored 
great numbers of mosquito larve. They found that the larva of this triton, as 
well as the adult, destroyed mosquito larve. 
In the section on “ Remedies ” under the head of the “ Practical use of natural 
enemies of mosquitoes,” mention is made of the importation into Hawaii of the 
western salamander or newt (Diemyctylus tortosus) which has been kept for 
several weeks in an open tank by Mr. Albert Koebele, with the result that they 
devoured all of the mosquito larve in the tank. 
The aquatic larve of our terrestrial salamanders are predaceous and feed on 
mosquito larve as well as other aquatic insects. Mr. W. L. McAtee of the Bio- 
logical Survey has fed the larve of Amblystoma opacum with larvee of Chaoborus 
