14 THE COCCIDAE 



insect can be written with an ordinary pencil, are the most 

 convenient. 



The student should supply himself with a good stock of slides 

 and cover- glasses. The slides should be of the ordinary size, 

 75 x 25 mm., with ground edges. There are two kinds, those known 

 as thin or extra thin which have the advantage that twice as 

 many can be stored in an ordinary slide box, those known as thick 

 slides which require more space but they are not so easily broken. 



The cover-glasses should be No. 1 as to thickness and not 

 over 15 mm. in diameter and preferably only 12 mm. The use of 

 small covers, where the great majority of the objects to be mounted 

 are minute, saves time in locating the specimens under the cover. 



Slides and cover-glasses as they come from the dealer are 

 greasy and should always be cleaned before using. The slides 

 should be placed in water containing about five per cent of 

 ammonia or in 95 per cent alcohol acidulated with one per cent 

 of hydrochloric acid. The cover-glasses should be placed in acidu- 

 lated alcohol. They should be added to the solution one at a time sc 

 that the solution will cover all parts and should remain in it for 

 five or six hours. The slides and covers should be wiped with a 

 towel or piece of cheese cloth and stored in covered jars until 

 needed. 



Tools. The person making preparations of coccids should be 

 provided with the following tools: 



1. Forceps. The forceps should have fine smooth points 

 without corrugations of any sort. The spring should be weak. 

 This serves a double purpose, they will not tire the hand so 

 quickly and there is less danger of injuring the specimen, since 

 only slight force is needed to close them. Two pairs of such 

 forceps will often be found convenient. 



2. Dissecting Needles. The needles with a fixed ebony or 

 aluminum handle with straight points are best. Two are essential, 

 more will be found convenient. 



3. Embryo Knives. Dissecting needles with a spear point, 

 one with a double cutting edge and one with a single cutting edge. 



4. Section Lifter. One with a small, thin, flexible blade. 



5. Scissors. A pair 115 mm. long with fine curved points. 



6. Pipettes. The rubber bulb should hold 2 cc. and the 

 glass tube should be long, straight, and with a large opening. One 

 at least for each kind of solution used. 



7. Brushes. Two artist's sable brushes of different sizes will 



