OH the CEstridce. 77 



was powerfully adhesive, it did not, in any instance, prove 

 successful ; owing, chiefly, to the cows being turned out at 

 night, when, from some disturbing cause or other, the plastered 

 leather became gradually detached, and I failed to hag my 

 game in the little muslin pouch provided for its reception. 

 Having foreseen that the chances of failure in this way were 

 very great, and as it was evident that the vulgar mode of 

 squeezing or popping out the larva through the small opening 

 in the hide, by which the insect obtains air for respiration, 

 must prove fatal to it, I determined to enlarge the orifice very 

 freely by means of a director and probe-pointed bistoury, 

 and then pressing the sides of the sac firmly and carefully 

 the safe delivery of the insect was easily effected : by this 

 plan I have been fortunate enough to obtain, as will appear 

 in the sequel, seven specimens of the fly. 



May 11. — The larvae removed to-day were most of them of 

 premature growth, being of a beautiful pearly white, and 

 others of a very pale tawny colour with darker patches. 



May 24. — Several specimens of full growth were removed 

 during the last fortnight, and I noticed for the first time, the 

 collapsed state of the swellings from which the insects had 

 taken their departure. 



June 7. — The preceding two weeks have procured me many 

 specimens, some quite white and others dark tawny. 



July 23. — Continued procuring larvae up to this day; with the 

 exception of a few remaining in two or three cows, they have 

 all quitted their snug warm quarters in the midst of plenty, 

 to hazard the many casualties of a new state of existence. 

 The greatest number I noticed in any one animal was about 

 100 ; they were in a heifer which had been much turned out ; 

 T succeeded but in one instance to obtain a specimen, which 

 had come out spontaneously ; the larvas were placed on fine 

 mould, kept slightly damp, in a garden flower-pot, and 

 covered with gauze, the perfect insects appeared at the fol- 

 lowing dates : — 



July 10. — A male, the shell from which it came forth contained 

 a good sized drop of a limpid, brownish, purulent fluid. 



July 16. — A very fine male. 



July 25. — A female. 

 August 2. — A female. 



August 20. — A female, the larva of which having been put 

 aside by itself on July 11 proves the intermediate stage to 

 have been exactly forty days. 



