536 NATURAL HISTORY OF ARTHROPODS. 



To the genus Vespa belong the shorter bodied wasps with folded wings, which are 

 commonly known as " hornets " or yellow-jackets." These build nests consisting of a 



series of combs arranged one below another, and all en- 

 closed by a spherical or egg-shaped envelope. The 

 " white-faced hornet " ( Vespa maculata) is our largest 

 species. It is the American representative of the 

 European Vespa crabo which has been introduced 

 into this country. 



In the tropics the nests of Vespa, often attain an 

 immense size. The nest of a Ceylonese species reaches 

 FIG. 662. Vespa maniiata, white- a length of six feet. A common South American form 



faced hornet. 



is made ot such thick and firm paper that it resembles 



pasteboard. The outer layer is so fine in texture that it can be readily written upon 

 with ink. 



No parasites in the nests of wasps have been discovered as yet in this country, but 

 in Europe a number of such species have been found. T\vo species of Ichneumonid, 

 one of which is Amomalon vespantm, infest the larva 1 . The larva of Volucella and 

 Anthomyia incana destroy the larvae in their cells, while the adult wasps are infested 

 by RMpiphorus paradoxus, a beetle allied to Stylops. 



The succeeding two families, ANDRENID^E and APID^E, have been grouped together 

 under the sub-sectional or tribal name of MELLIFERA, or Honey Gatherers. As dis- 

 tinguished from the fossorial Hymenoptera, which we have just considered, this group 

 may be characterized as follows : In the solitary species there are but two sexes, male 

 and female; but in the social ones another is added in the shape of a neuter, abortive 

 female, or worker. The females and workers, except in the hive and parasitic bees, 

 are furnished with apparatus for carrying pollen, and are armed with a sting. The 

 antenna? of the females and workers are twelve, and of the males thirteen-jointed. 

 Nearly all in the larva state feed upon pollen or honey stored up by the adults, while 

 some are parasitical, devouring the food stored up by other species. 



The family ANDRENID.E includes the so-called "solitary bees." In this family the 

 mentum is elongate, and the labium at its extremity is either spear-shaped or cordate. 

 From this reason the group has been divided by certain authors into the Acutilingu.es 

 and Obtusilingues. The labium and terminal maxillary lobes do not form an elon- 

 gated proboscis. The trochanters and femora of the hind legs in the females are 

 generally pollenigerous. These insects are all solitary, and each species consists of 

 but the two sexes. The females collect pollen, which they make into a paste for their 

 cells. Nearly all the species burrow into the ground, forming their cells in either a 

 straight burrow, or one which has branches with a common mouth. Certain species, 

 however, use interstices in walls and bramble canes in which to make their cells. 



The two genera, Colletes and Prosopis form the group known as Obtusilingues. 

 The species of the genus Colletes usually burrow into the ground to a depth of from 

 eight to ten inches, forming a simple burrow in which are placed six or eight cells 

 formed of a thin, transparent membranous substance. One species, however, has been 

 found making its cells in the chinks of a stone wall which had previously been filled 

 in with earth or soft mortar. Prosopis has been considered parasitic, but the observa- 

 tions of Frederick Smith have proved the contrary. Its cells are commonly found 

 in the hollows of bramble sticks, and an instance is recorded in Avhich a hollow piece 

 of flint stone was used for this purpose. A species of Stylops infests this genus. 



