125 



2. Allow to remain in alcohol fifteen minutes 

 to harden somewhat. 



3. Remove one by one. Cut off with a fine 

 scissors the legs and wings. Make a minute 

 incision into both the thorax and abdomen, e.g., 

 holding the mosquito carefully between the finger 

 and thumb, slice off with a sharp razor a 

 portion of the dorsum of the thorax, and a 

 minute portion of one side of the abdomen. 

 This allows more perfect penetration of fluids. 



4. Replace in absolute alcohol' (some authors 

 recommend boiling in alcohol, as the air in the 

 tracheae is expelled, and the alcohol then pene- 

 trates completely), allow to remain one to two 

 hours. This, which is to ensure complete dehydra- 

 tion, is the most important of operations, and upon 

 it depends the success of the embedding. Make 

 two or three changes, using alcohol to which CUS04 

 has been added. 



5. Remove from alcohol and place for ten 

 minutes or so in xylol. When the thorax becomes 

 transparent, the mosquito should be removed, as 

 too long a time in xylol produces much hardening. 



6. Place for ten minutes in paraffin {vide p. 46) 

 kept melted in a watch glass on the heated metal 

 slab. 



7. Smear a clean watch glass with a little 

 glycerine, and fill with paraffin heated somewhat 

 over melting point ; transfer the specimen to this 

 with a warm forceps to avoid cooling the paraffin. 



8. Arrange the specimen as required. As 

 soon as the surface of the paraffin has set, plunge 

 the whole mass into water, as paraffin rapidly 

 cooled is more homogenous. 



I. For finer work pass through thirty, fifty, and seventy-five per cent, to 

 absolute. See, however, examination of separate organs. 



