77 



2. Carefully observe the length and thick- 

 ness of the respiratory syphon. 



3. Note the absence of palmate hairs. 



4. Determine whether the larvae examined 

 are Culex, Stegomyia, Taeniorhynchtis, etc. 



The characteristics of the larvae of Culex 

 appear to be : — 



(i) Antennae not markedly curved, or sickle- 

 shaped (Fig. 23). 

 (ii) The respiratory syphon long, but not 

 extremely slender as in Taeniorhynchus 

 (Fig. 22). 



5. Determine the relative length and breadth 

 of the various larvae : — 



In Culex, the length is to the breadth as 4 : i. 



In Taeniorhynchus ,, ,, ,, g-12 : i. 



In Stegomyia ,, ,, ,, 2:1. 



In any particular species there will be deviations 

 from these, but broadly speaking, these differences 

 hold good. 



The Larvae of Anophelines 



To collect the larvae. — Necessary apparatus : — 



1. An ordinary spoon, dessert or table-spoon 

 size is most convenient, but a tea-spoon does well. 



2. A white enamel tin or large cup, or an 

 ordinary bath tin. 



3. Bottles, specimen tubes, paper, pencils, 

 etc. 



Procedure. 



I. By inspection. — Inspect closely the surface 

 of any small puddles that have been in existence 

 sometime. Examine especially small rockpuddles. 



