IMPROVEMENT OF TECHNIQUES FOR AGE GRADING HEMATOPHAGOUS INSECTS - OVARIAN OIL-INJECTION AND OVARIOLAR SEPARATION TECHNIQUES

After injection of oil into tile oviduct of hematophagous Diptera, the ovarioles become completely separated from each other allowing examin ation of a large number of undamaged ovarioles, an important advantage over other techniques for accurately determining tile physiological a ge of mosquitoes. The technique has been simplified and improved, espe cially by using a sodium chloride-glycerol-formaldehyde mixture for mo unting preparations, which; are more convenient and permanent for exam ination of the ovarioles. The difficulties of using the technique, the ir possible causes, and possibilities for overcoming them are describe d. Similar results can be obtained with an alternative technique, the ovariolar separation technique, using strongly diluted Carnoy's soluti on, which leaves ovaries in a fixed condition. Both techniques can be used for several hematophagous dipteran groups.