1885-86.] Edinburgh Naturalists' Field Club. 333 



freely. It is in the larva stage, and not in the imago or perfect 

 form, that the fly is carnivorous. The food of the Blow-fly consists 

 largely of juices, and all forms of excreta and refuse which have 

 become dry and encrusted, and it is on the latter that the tongue 

 of the Blow-fly is most effective. I have said that the saliva acted 

 as the vehicle which conveyed the food to the mouth and sucking- 

 crop : it is also highly probable that it is used to cleanse the lobes 

 from accidental impurities, or substances disliked by the fly ; for if 

 a brush is dipped in oil and drawn down the fissure formed by the 

 closing of the lobes, the trunk will be extended, the lobes opened, 

 and a copious flow of saliva poured out, which quickly covers the 

 lobes. This continues for a few seconds, when the lobes are 

 closed, and the trunk resumes its usual position. The same effects 

 follow the application of vinegar, beer, &c. ; while no such result 

 follows when milk, tea, soup, or an}; thing of that nature is given. 

 Again, it has been thought that the false tracheae, with their 

 thousands of little forks, acted as a grating through which the food 

 of the fly was sifted ; but if the fly is put in the live-box with a 

 drop of thin clear jelly containing a few air-bells, and if, when 

 the fly is sucking, the course of these air-bells is watched, they 

 will be found to move towards the centre of the lobes, and finally 

 to disappear down what, for description's sake, may be called tlie 

 throat of the fly. Had the tracheas acted as a grating through 

 which the food of the fly was sifted, these air-bells must have 

 moved and disappeared in some other direction. 



As I have found my own observations on these points so much 

 at variance with what has been written on the Blow-fly, I have 

 ventured to bring the subject under the notice of the Ckib, in the 

 hope that if any of our members are interested in insect life, they 

 may investigate this matter further, and probably throw some 

 additional light on the subject of " the tongue of the Blow-fly in 

 relation to its food." 



At the fifth meeting (March 5, 1886), Mr W. E. Hoyle, M.A., 

 M.E.C.S., F.R.S.E., gave a lecture "On the Structure of Small 

 Parasites, as demonstrated by Ribbon Section-cutting, with prac- 

 tical Illustrations." The lecture was highly appreciated by the 

 members, both on account of its interesting nature and of the 

 clever manipulation by which it was illustrated. Two different 

 forms of ribbon section-cutters were exhibited and described ; and 

 one of them was shown in operation, the organism being cut from 

 end to end in continuous attached sections, so as to permit of an 

 examination of the entire structure under the microscope. 



At the sixth and concluding meeting (April 2, 1886), Mr Alex. 

 Frazer, M.A., optician, exhibited and described two pieces of 



VOL. I. z 



