206 



Lehmann, Odell, Whitley, Tyrrell, McConnell and Fletcher supplied 

 and arranged the microscopes and slides, and explained to the observers 

 the objects exhibited. The Club i;. much indebted to these members 

 for the assistance given, and the Council tenders them its sincere 

 thanks. 



-:o: 



THE MICROSCOPE IN ENTOMOLOGY. 



By W. Hague Harrixqtox. 



(Read at Microscopical Soiree, i8ih February, i8g2 ) 



To the student of Entomology a good microscope and the know- 

 ledge of its use are indispensable when he desires thoroughly to 

 decipher the characters upon which are based the determination and 

 classification of his specimens. Many insects are so small that ihe 

 naked eye can scarcely determine even the order to which they belong, 

 and even the large species are separated frequently by the formation of 

 the mouth parts, or other structures which require to be much magni- 

 fied before they can be satisfactorily distinguished. The microscopist, 

 therefore, can always, in the extensive field of Entomology, find ample 

 scope for the useful employment of his valued instrument, and can 

 always obtain abundant interesting slides for his cabinets. Hundreds 

 of the smaller species can advantageously he mounted whole, and will 

 make very fine slides. Especially suitable for this treatment are the 

 minute parasitic hymenoptera, many of the smaller diptera, the plant- 

 lice and scale-insects among hemiptera, various families of minute 

 coloeptera, etc. All the orders will, in the earlier stages of the egg and 

 the larva, furnish unlimited supplies of curious, beautiful and instruc- 

 tive mounts. 



Of special organs or structures which may form worthy objects of 

 examination, there is a wonderful variety, a portion of which only can 

 be now indicated. Each insect, as you are aware, is composed of three 

 distinct regions — the head, the thorax and the abdomen — although in 

 some species these may be so modified and consolidated as not to be 

 readily apparent. The insect also bears externally certain appendages, 

 and is furnished with an elaborate apparatus for digestion, sensation, 

 respiration, motion and generation. 



