2 A Monograph of Culicidae. 



was frequented by numbers of the larvae of Anopheles bifurcatus 

 and A. maculipennis every year. Two years ago its surface 

 became smothered with Lemna minor, Linn., and Lemna arrhiza, 

 Linn., no Anopheline larvae could then be found. As this 

 was the only breeding ground near, both species have practically 

 died out. 



This small yet widely distributed genus of floating plants 

 evidently has a very marked effect upon the frequence of 

 Culicid larvae in natural and artificial collections of water. 



The little Lemna arrhiza, or the Rootless Duckweed, occurs 

 in Asia, Africa, South America and Europe, and apparently has 

 the same effect as the larger L. minor. 



THE "LOBSTER-CLAW" PLANT (HELICONIA BRASI- 

 LIENSIS) AS A BREEDING PLACE OF MOSQUITOES. 



Mr. E. E. Green states that the flowers of this plant "are 

 constructed so as to contain a considerable quantity of water, 

 probably derived from rain. I have recently collected about 

 half a pint of this liquid and find it to be swarming with the 

 larvae of two species of mosquito — Stegomyia scutellaris and 

 Desvoidea obturbans. This habit renders this plant an unfortunate 

 neighbour. If it must be grown, it should be relegated to the 

 more distant parts of the shrubbery and not cultivated in close 

 proximity to the bungalow " (" Tropi. Agriculturist," N.S. xxv. 2, 

 p. 297, 1905). 



BROMELIAS AND BAMBOOS AS BREEDING PLACES 



OF MOSQUITOES. 



Dr. A. Lutz in a valuable paper (Waldmosquitos und Wald- 

 malaria, Centralbl. f. Bakt, etc., I., Abt. Originale, Bd. XXXIII., 

 No. 4, pp. 282 to 292, 1903) points out how various Culicids may 

 breed in the water collections of Bromelias, and figures such as 

 lechnea tinctoria, Mez. ; Nidularium ampullaceum, E. Morr ; 

 Eriocaulon vayinatum, Kcke. ; and Freycinetia arnotti, Gaud, as 

 examples, also a Pitcher Plant (Nepenthes gracilis). Breeding 

 in such places he mentions Myzomyia lutzii, Trichoprosopon 

 nivipcs, and others. 



Dr. Leicester, working in Malaya, finds that particular species 

 not only live in their larval stage in the small collections of 

 water that collect in cut bamboos, but that they enter the holes 



