260 ENTOMOLOGICAL NEWS. [June, 'lO 



"Mansonia titillans is one of the commonest mosquitoes of 

 tropical South America, abounding especially in coast regions 

 and along the banks of rivers. It is present with us through- 

 out the year in greater or less numbers. Even in the height 

 of the dry season it is here to annoy us. The larva has re- 

 mained unknown. I had been hunting for it, and had search- 

 ed to no purpose swamps, trenches and water-holes at morn- 

 ing, noon and evening. I also had tried over a dozen times 

 to get the larvae from eggs by allowing the mosquitoes to 

 suck my blood and then enclosing them in jars. In no in- 

 stance did even one so much as deposit eggs. Now it hap- 

 pened that I was dipping with a calabash in one of the Kitty 

 sweet-water canals for larvae of two other mosquitoes, which 

 can always be found there. The water was pretty thickly 

 coated with the aquatic plants Salvinia and Pistia. One of 

 my dippings brought up a portion of Pistia, which I threw 

 back. After pouring out most of the water I noticed a large 

 stout whitish brown larva wriggling at the bottom of the cal- 

 abash among the thick rust brown stuff dislodged from the 

 roots of the plant. At first sight I thought it was a dragon- 

 fly larva, but, its actions making me suspicious, I turned it in- 

 to my collecting tin for further examination. On arriving 

 at the museum a cursory examination showed it was a mos- 

 quito larva new to me, and the biggest I had as yet come 

 across. Next afternoon I returned to the same trench and 

 soon discovered that by taking up Pistia and shaking the 

 roots vigorously in water in my calabash that I could get in 

 a short time quite a number of these big brown larvae. Last 

 week the adult mosquito began coming out and it is Manson- 

 ia titillans. 



"The siphon of the larva is characteristic, being short, con- 

 ical, tapering to a point, black at the apex, and almost in a 

 straight line with the length of the body. Its resting position 

 is also characteristic, it hangs vertical, it likes to suspend it- 

 self among the roots of the green rosette-like plant Pistia and 

 its general rusty brown color harmonizes well with the color 

 of the muck about the roots. In lifting the plant from the 



