The Microscope and Biology. By W. Wesche". 411 



Our common wild bee (Bombus pratorum 2 ?), has some very 

 large pollen granules inside, which are probably from the flower 

 of the hollyhock (Althcea). 



Hallictus leucozonus 2 , another wild bee, has made a meal of 

 pollen, which, however, is partially digested. 



The food of a wasp ( Vespa vulgaris) was less easy to determine ; 

 it was a fine reddish, granular mass, which had cracked across. 

 This is the way that albumen behaves when mounted in xylol 

 and Canada balsam, and I conclude that some juices of animal 

 or insect have been the staple part of its meal. There was also 

 some debris in the thorax. 



Of all insects the Odonata (dragon-flies) are the most voracious, 

 and as they only partially break up their prey, it is comparatively 

 easy to identify fragments ; for example I recognised many 

 portions of the wings of Diptera. This is a part that is often 

 rejected ; it is not an unusual sight to see a dragon-fly capture a 

 moth, immediately followed by the slow flutter of the four wings 

 to the earth, bitten off by the captor. I have a few preparations 

 of these insects, which are from all parts of the globe ; from an 

 examination of the abdomen of these (there is not one that is not 

 full of undigested food), I should think that the favourite meal is 

 that on some dipterous insect, particularly the haunter of streams. 



In Orthetrum ccerulescens F. I have seen some minute tarsi 

 and claws that probably belong to small Ephydridse, and I can 

 recognise a tarsal joint, a base of an antenna, the characteristic 

 interior tubes of the head, several parts of the wings, and part of 

 an eye of an unfortunate Chironomus. 



An Archibassis, from Borneo, has made a meal of a fly ; I am 

 able to say, from the character of one of the receptacula seminis, 

 that the prey was a female, one of the large Muscid family, 

 probably an Anthomyid ; a part of the tracheal of the labium, and 

 several pieces of the eye are also recognisable. 



An American insect from Indiana, U.S.A., Enallagma civilis, 

 was very thorough, and, as might be expected from an inhabitant 

 of the Great Kepublic, exhaustive in his method. He began the 

 day on a Chirononucs, then devoured a large larva of Lepidoptera 

 (this last was interesting, as usually the prey is caught on the wing) ; 

 and completed the third course of his meal with another fly. The 

 caterpillar was easily identified by the claws of the prolegs, but the 

 presence of pollen granules in the abdomen of the dragon-fly rather 

 baffled me, till I saw that they must be the food of the larva, which, 

 like its captor, was overtaken by fate soon after a meal. 



I now turn to the more difficult part of my subject, the 

 Diptera, though in this order I can offer a more comprehensive 

 survey, as in my study of this branch over 1500 slides were exa- 

 mined with high powers, and often with a magnification of over 

 1000 diameters. The general appearance varies, but not more so 



