424 Transactions of the Society. 



6. Recognisable remains of prey are found in a number of 

 inandibulate insects. 



7. Also in a few Diptera. 



8. Remains identified as scales and hairs of Culcx. 



9. The food of non-predaceous flies is discussed, and in one or 

 two cases the pollen is recognised. 



10. Food which must have been eaten in the larval stage is 

 found in the abdomen of the female imago of Oncodes gibhosus L., 

 and not in that of the male. 



11. Spores of rust or mould, or mildew, are found in the intes- 

 tines of many Diptera, from New Zealand as well as England. 



12. Larvae are found in the abdomens of several viviparous 

 flies — Phoroccra, Oliviera, and Plagia. 



13. Differences are noted in the armature of the mouth of the 

 males and females of some Phoridse. 



Methods of Work. — I use a § in. for general, and a | in. capable 

 of working at a long distance, for particular examination. With 

 them I use a powerful substage condenser (the ordinary Abbe is 

 not sufficiently powerful). A ^ oil-immersion, with a tube-length 

 of 25 mm., is occasionally employed. 



Examination through the slip is sometimes necessary, when 

 the part desired to be seen is on the under side of the preparation ; 

 an eye-piece of high magnification is used with the § in., and 

 answers very fairly well. The satisfactory working of these 

 objectives entirely depends on the substage illumination ; the con- 

 denser must be powerful, and the iris diaphragm carefully used, 

 as the objects focused are often on the surface, or even between 

 plates of only semi-transparent chitin. 



In conclusion, I have to express my great obligations to 

 Mr. Walter Imboden, F.R.M.S., for his most valuable assistance 

 in so kindly photographing the abdomens of various insects. 



