Collecting and Laboratory Methods 199 



manipulated that they will stay there while all but a 

 very little water is poured off; what remains may, 

 with the larvae, be poured into one of the collecting 

 jars. If there are many wigglers in the dipper, this 

 is a much quicker method than picking them out 

 and placing them in the jar with the pipette. A 

 stick may be tied to the handle of the dipper if it is 

 not long enough. Some people prefer a coffee 

 strainer, but I think it is harder to remove the larvae 

 from this than from a common dipper, and they are 

 more likely to be injured. Many species can be car- 

 ried a long way in the jars, and even several days' 

 journey will not hurt them if the jar is aired occa- 

 sionally, and they are not shaken about too much. 

 This last may be averted by filling the jar pretty well, 

 but not entirely, with water and putting in Spirogyra 

 or water weed, which not only prevents jarring, but 

 freshens the air somewhat. I have sent the larvae 

 successfully in this way for short distances by mail. 



On reaching the laboratory the larvae should be 

 sorted out and identified alive if possible. Often 

 this may be done with a strong hand lens mounted 

 in a holder, if one has no compound microscope. 

 The larvae may be examined alive in a hollowed 

 glass slide ; they will usually, after the first minute 

 or so, keep fairly quiet, and if they do not, a cover 

 glass on top of them for a few minutes will not hurt 

 them. The chief thing is, not to let them dry. Too 

 much light will make them restless. If a hollowed 

 glass slide cannot be obtained, use a slide ringed 

 with asphaltum, clay or paraffine, or even a wet 

 cotton ring. The larvae may be bred in jars or 



