3 2i POPULAR SCIENCE MONTHLY. 



Wasps and hornets are not without their enemies, for their nests 

 are frequently infested by parasitical insects that feed upon their 

 grubs. According to Shipley, " In the tropics some species are 

 attacked by fungi, the hyphse of which protrude between the seg- 

 ments of the abdomen and give the wasp a very extraordinary 

 appearance." 



From the wasps and hornets I next pass to a consideration of 

 a few of the species of bees, omitting, however, anything in refer- 

 ence to the common hive bee (Apis mellifica), of which insect 

 entire volumes have been written. 



Hundreds of species of wild bees are now known, and they are 

 to be found in almost every part of the world, and doubtless many 

 species yet remain to be described by the entomologists. Those 

 found have been arranged in the two families Andrenidm and 

 ApidcB by Kirby, and are subdivided into a number of genera. 

 In the first family all the species are solitary of habit, while in 

 the second both solitary and social species are found. True honey- 

 bees are found wild in this country, and the species most nearly 

 allied to them with us is the common bumblebee (Bombus), of 

 which genus upward of fifty species or more occur in North 

 America. This bee, or rather a queen of this species, hibernates 

 all winter, but early in the spring makes her nest. This may be 

 under any old log or piece of turf or the vacated nest of a field 

 mouse. A dozen eggs or so are laid in a mixture she makes of 

 pollen and honey, and the young appear in series from egg to 

 imago, the period of development being of no great length. From 

 this time on the study of the colony is full of interest, but the 

 sequence of events is not altogether unlike what has been de- 

 scribed above for the wasps, the nature of the nest and the fate of 

 the eggs when first deposited being the main difference. 



Bumblebees are preyed upon by a variety of parasites, the 

 most curious being a species of Apathus, an insect so closely re- 

 sembling its host that it requires the eye of an expert to detect 

 the one from the other. Many of us are familiar with the history 

 of the tunnels in posts, planks, and similar places made by that 

 large species known as the Virginian carpenter bee (Xylocopa vir- 

 ginica) ; and then, too, we have its pretty little ally, the bright 

 pea-green Ceratina dupla, that constructs similar tunnels in such 

 plants as have a pithy center, as reeds and elderberry bushes. 

 These tunnels in either case are intended to hold the cells in 

 which the eggs are deposited and the young reared. The habits 

 of the tailor or leaf-cutting bee are even still more interesting 

 (Megachile centuncularis). They have strong, sharp-cutting jaws, 

 by means of which they cut away bits of leaves to be used in the 

 formation of their cells, the site of the nest being in elder stalks 

 or under planks or in the hollows of certain trees. Their very 



