PREFACE 



At the request of several medical men I have prepared the -following 

 short key to the common anopheline larvae of the Malay Peninsula as -a' -sequel' 

 to my "Short Key to the Anopheline Mosquitos of Malaya," which appeared a short 

 time back. 



There are certainly advantages in being able to identify the larva. For 

 instance if it be examined immediately it is caught, and the species determined, 

 one is saved the trouble of looking after a number of hatching -out bottles for 

 perhaps a considerable period. Moreover in hatching-out bottles many larvae die, 

 and then if they have not been already identified valuable information may have 

 been lost. 



A disadvantage is that a microscope must be used; which is not 

 necessary for the adult. 



The larva is collected in the various ways which the collector has 

 devised, it is brought home in the waters of its birth, and forthwith killed by being 

 placed in a mixture of 50% alcohol and 4% formalin (in which it can also be 

 preserved,) or it may be allowed to die from natural causes. For examination under 

 the microscope it is placed on a glass slide and covered with a glass slip: a one 

 sixth-inch objective gives sufficient magnification. 



It is possible, if the larva is well-grown, to identify every species of 

 Malayan anopheline with certainty. But this Key applies only to the commoner 

 species. The rare species are. not included in the Key. 



Some of these rare species are so like common species, in their larval 

 characteristics, that without the most careful examination a mistake might be 

 made when trying to identify a specimen, but then no great harm would result in 

 mistaking these rare species for even bad carriers, unless too much significance is 

 attached to the finding of what would probably, owing to the rarity of the species, 

 be only a single specimen. 



On the other hand some rare species have very distinct larval 

 characteristics, for which the observer will find no counterpart in the following 

 pages, but they can be of little or no epidemiological importance and can be 

 disregarded.* 



The larva must be well-grown, if this Key is to be used; because if 

 the larva is young, in some species it approximates in character so much to other 

 species that it might be confused with the other species. 



No antimalarial campaign can be intelligently and economically carried 

 out without accurate measurement of all the factors concerned in the production 

 of the disease, and the discovery of one larva of a carrying sp'-oies should not be 

 a signal for panic-stricken antimalarial works. It should only be considered as 

 possibly an important piece of epidemiological evidence, and as only a very gross 

 piece of espionage which has been accomplished by the Intelligence Department 

 in the campaign. 



I am greatly indebted to Miss K. O' Connor for the trouble which she 

 has bestowed upon the figures. 



#It would be interesting to refer such forms in their preserving fluid to some expert. 



