MOSQUITO FISH—JORDAN 365 
streams and marshes about Singapore, Mandalay, and Bangkok 
either have been stocked by Dr. Herre, or are soon to be so, 
The fish is now distributed to southern Japan and China, and ulti- 
mately will be, I hope, to all the malaria-burdened world. 
A native of warm regions, we are not sure how much cold it will 
stand. Last winter in California, the temperature dropped two or 
three times to about 30°, but none of the fish seemed to suffer. In 
early November the old fishes slip to the bottom in mud and weeds to 
keep warm, but the later born of the flock may be seen near the sur- 
face on any of the so-called winter days of central or southern 
California. The director of the Illinois pond at Carbondale reports 
that a foot and a half of ice did not kill any of them last winter, as 
they were all hibernating at the bottom of the pond. In their native 
regions, snow and ice are unknown, but they do not seem to mind 
moderate cold if they are allowed to lie still and are not expected to 
function. As to heat, Hildebrand reports that in nature he has 
found Gambusia in water having a temperature of 102° F. When 
held in containers they usually die when 100° F. is reached. They 
feed on flies and mosquitoes by choice, rejecting wasps, beetles, butter- 
flies, or larger insects. I have seen them leap out of the water to 
seize an incautious fly alighting on the edge of their pond. 
These fishes are light greenish brown in color, the fins speckled, 
but no conspicuous markings anywhere. In the adult there is usually 
a black shade or bar under the eyes, and the gravid females develop a 
black area on the side under the skin. The female is 214 inches 
long, the male about an inch shorter. About 10 females are born to 1 
male. The eggs are hatched in the body of the female, 6 to 10 ina 
brood, there being 4 or 5 broods between March and September. 
This is recorded in Georgia, with Gambusia holbrooki. In Cali- 
fornia, with Gambusia patruelis, I notice but two or three broods in a 
‘season. The young when born are transparent, with big black eyes, 
and are about a fifth of an inch in length. 
A certain number die when first caught and placed in confine- 
ment. ‘Those that survive the first three days mostly live on in- 
definitely. It is therefore well to hold a consignment for a few 
days before taking them for a long distance. In summer time about 
150 can be transferred in July in a 50-pound lard can, and in October 
as many as 500. In summer time a wet jacket of burlap around a 
can is desirable, but ice and overaeration are both risky. 
Mr. Hildebrand does not discuss the artificial feeding of these 
fishes. The very young evidently feed on minute or tender alga, 
as desmids and Conferve. The adult, in default of mosquitoes, 
take kindly to Conferve. The Gambusias in my own pool are fed 
on goldfish food. The kind which is made of rice-flour pressed into 
flat cakes they eat eagerly, especially if cut or torn into very small 
