HOW TO KNOW THE IMMATURE INSECTS 



2. X.A.A.D. mixture: 



Xylene 4 parts. 



Commercial refined isopropyl alcohol 6 parts. 



Glacial acetic acid 5 parts. 



Dioxan 4 parts. 



Good for lepidopterous larvae and coleopterous larvae. 



3. K.A.A.D. mixture: 



Kerosene 1 part. 



95% ethyl alcohol or 



refined commercial isopryl alcohol 7-9 parts. 



Glacial acetic acid 1 part. 



Dioxan 1 part. 



Good for maggots, lepidopterous larvae, hymenopterous larvae and 

 pupae, coleopterous larvae and neuropterous larvae. But it does not 

 produce satisfactory specimens where larvae possess a thick exo 

 skeleton, namely wireworms and similar species or among some aqua- 

 tic insects especially immature stages of Zygoptera and Ephemeroptera. 



Larvae collected in the field are dropped into the killing solution 

 and kept submerged until they are completely distended. If narrow 

 vials are used for large larvae they should be places in a horizontal 

 position until the larvae straighten out and become firmly set. This 

 may take from one to several hours depending upon the species. At 

 the end of this period the larvae should be transferred to ethyl alcohol. 

 Larvae possessing a firm exoskeleton may be preserved in 75 7o ethyl 

 alcohol, while soft bodied forms killed in K.A.A.D. mixture should be 

 preserved in 95% ethyl alcohol to prevent any collapse. 



HOW TO REAR IMMATURE INSECTS 



For studying the life history or identifying the adult stage, the im- 

 mature insects are often reared in the laboratory. Rearing insects is 

 quite a technical job. The natural conditions under which the imma- 

 ture insects were found should be simulated as closely as possible. 

 The following is just a brief account of the more important aspects. 



1. Cage. — Screen cages of different sizes are desirable for rearing 

 immature insects. The food plant can be cultured in soil or in water 

 and put in the cage. For rearing a large number of isolated individual 

 insects it is usually difficult to provide a large number of cages and 

 bottles or vials are used instead. 



2. Food. — The kind of food material the insect feeds on must be de- 

 termined at the start. Ordinarily the rearing container is not large 

 enough for putting the entire food material inside, so fresh food should 

 be suppLed every day. For example, leaves or the other parts of 

 plants should be provided for the phytophagous insects and they al- 

 ways should be kept fresh. Insects that infest seeds and those that 



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