7 G 
A Monograph of Culieidae. 
Tha.xter as attacking small gnats (sp. ?) in North America, and 
called by him Empusa papillata, but these small gnats may 
not have been Culieidae. This latter parasite is confined to 
Diptera, and only found, we are informed, attacking minute gnats, 
particularly in the beds of mountain brooks on moist logs. 
CERTAIN WATER PLANTS INIMICAL TO THE LARVAE. 
Colonel Giles has noticed in the Benares Public Gardens, 
where there are scores of small irrigation tanks, that both Culex 
and Anopheles larvae were present in every tank save those that 
were covered with a peculiar floating water plant, looking much 
like young lettuce, which is spoken of by the natives as Jalkumi. 
In the tanks so planted the water was alive with young leeches 
and nematodes, but not a single mosquito larva. When intro¬ 
duced into a tank containing mosquito larvae, however, the 
plants appeared to exercise no hostile influence on their develop¬ 
ment, and for this reason Colonel Giles concludes that the plants 
simply act mechanically in the same way as an artificial cover. 
The plants, in fact, simply hide the water from a mosquito when 
searching for a suitable place in which to deposit her eggs. 
THE GEOLOGICAL DISTRIBUTION OF CULICIDAE. 
As far back as the Purbeckian Period we find traces of 
Culieidae. 
Brodie * describes a wingless gnat, with legs and antennae 
well preserved, from the Purbeck rocks of England, and named 
by him Culex fossilis. This unfortunately is the only old record 
I know of, but it shows us that the family was represented as 
far back as the Secondary Period. 
In the Tertiary ambers the mosquitoes are fairly plentiful. 
The genera Culex and Mochlonyx have been identified by Loew and 
Giebel both in America and Europe. Erom Aix and Utah the 
genus Corethra has also been recorded, whilst others have been 
obtained from the well-known beds at Florissant and in the Isle 
of Wight. Heyden also describes from Rott a species under the 
name Culicites in Tertiary strata, f 
* “Fossil Insects,” Brodie. 
t Bull. No. 31, “ Geolog. Survey,” U.S.A. 1886, p. 91. 
