MR. TUFFEN WEST ON THE FOOT OF THE FLY. 419 



It may be desiral^le to add a few words on the best plan of conducting observations 

 on these parts. Their action should be studied in living insects under the influence of 

 cliloroform, careful notes being taken of anything which may appear noteworthy, and 

 accurate drawings prepared from the life as well. It is of the greatest advantage to pre- 

 serve carefully all the parts that are examined ; for this purpose Deane's medium or 

 glycerine jelly suits exceedingly well ; some of the very delicate preparations, however, 

 can only be kept satisfactorily in a solution of chloride of zinc. The old plan of soaking 

 in caustic potash, crushing, washing, putting into spirits of wine, (or pressing and drying 

 first, and) then into turpentine, and lastly into Canada balsam, is perfectly useless, except 

 in rare instances where points connected with the structure of the integument have to be 

 made out. Of course the parts should be viewed from above, from below, and in profile, 

 in order to gain exact ideas of their relations. The binocular microscope, however, promises 

 to diminish vastly the difficulties which had until quite recently to be encountered, as 

 by its use the parts may be clearly viewed, just as they are, without preparation of any 

 kind. 



EXPLANATION OE THE PLATES. 



Plate XLI. 

 DIPTERA. 



The figures represent the feet of different flies as named : — a indicates the view of the parts on their 

 under surface; b, the same on their upper surface; c, profile view. The foot represented is ahvays that 

 of the anterior leg, on the left side, unless it is otherwise distinctly stated ; the sex of the insect, when 

 certainly observed or known, is also mentioned. R is used for a leg of the proper right side ; L, of the 

 proper left side: 1, 2, 3, for the anterior, middle, and hind legs respectively. 

 Fig. 1. 'S\ov;-{[y {Musca vomitoria), 2 • 



Fig. 2. House-fly {M. domestica), $ : d, appearance of the parts when in action, from behind. 

 Fig. 3. Baker- fly {Sarcophaga) : L 3. 

 Fig. 4. Drone-fly [Eristalis tenax). 

 Fig. 5. Asilus crabroniformis, $ : L 3 

 Fig. 6, Gad-fly [Tabanus bovinus), 2 

 Fig. 7- Wiagio scolopaceus. 

 Fig. 8. Echinomyia grossa. 

 Fig. 9. Volucella plumata. 

 Fig. 10. Scatophaga stercoraria, 

 Fig. 11. Syrphus balteatus, $ 

 Fig. 12. Sargus cuprarius, 9 

 Fig. 13. Bibio Marci, 2 ■ 

 Fig. 14. Borborus eqymus. 

 Fig. 15. Piophila casei. 

 Fig. 16. Ephydra riparia. 

 Fig. 17- Midge {Psychuda). 

 Fig. 18. Sheep-tick. 

 Fig. 19. Hippobocide fly. 



VOL. XXIII. ; ?> T 



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