Page:The New International Encyclopædia 1st ed. v. 20.djvu/396

WASP. 328 WASP. South American species are so regularly shaped and so compact and solid as to look like a stone. Vespa oricntalis mixes a considerable quantity of earth with the paper which it uses in its nest, and there is a nest in the British museum from Bahia supposed to be that of a social wasp, the outer wall of which is apparently formed en- tirely of earth and is one-quarter or one-half of an inch thick. The comb inside appears also to be formed of clay, and the whole seems an elaborate construction in pottery. Sharp sug- gests that it may possibly be the production of a eumenid wasp which has taken on social habits. The sting of most of the social wasps is very severe, but the wasps themselves are not danger- ous except when disturbed. When they are fly- ing about they are perfectly harmless unless at- tacked or irritated. A person may stand close to a wasp nest without risk if he stands motion- less. In fact, a wasp may settle upon a person with no danger of stinging unless some move- ment is made. The solitary wasps belonging to the Vespoidea resemble greatly in haljits the solitary wasps of the superfamily Sphecoidea, although they dif- fer in important structural characters. The family Pompilidce is an extensive one, more than a hundred species being found in the United States. They may well be known as the 'spider wasps,' since they all, so far as knom, store spiders in their burrows. As a rule they dig burrows in the ground or utilize excavations made by other insects. Some dig their burrows before they catch their spiders and others reverse the process. One species has been seen carefully to hang its spider on the branch of a plant until the burrow was completed. The tarantula killer (q.v.) of the Southern United States is a mem- ber of this family. The so-called 'potter-wasps' of the family Eumenidte belong to this group, and construct globular cells of clay or sand attached to a twig by a narrow petiole. These little wasps store up caterpillars, sawfly larva;, and beetle grubs for their young. Each cell is completely filled and contains a single egg of the wasp. The wasps of the parasitic families Sapygidse, Sco- liidae, Myzinida% and Tiphiida-, as a rule, lay their eggs upon the bodies of the larvie of other insects, especially beetle larvse. The true .solitary wasps of the superfamily Sphecoidea have been divided into 12 families, and comprise many of the most interesting of in- sects. They usually construct cells in subterra- nean burrows, each coll provided with para- lyzed insects for their larva>. In their liahits the Band wasps or 'digger wasps' are rather typical of the group, e.g. the great digger wasp liSphecius sprcioiius stores the large cicadas or harvest-flies in deep burrows made usually in clay soils. A burrow consisting of a sloping entrance six inches long, turning at right angles and extending for several inches farther and ending in a globular cell an inch and a half in diameter, is previous- ly prepared by the mother wasp. Sometimes the main burrow has several branches, each termi- nating in a similar cell. After a burrow is pre- pared, a cicada is captured and paralyzed by its captor's sting. The cicada is then carried with great difliculty up a trunk of the tree for some distance in onlcr that the wasp may fly oliliquely downward to her nest, the weight of the cicada being so great that she cannot fly with it hori- zontally or upward. The terminal cell being reached, an egg is laid under the middle of the victim's body, upon which the footless larva of the wasp begins to feed as soon as hatched. In the course of a week the larva spins a white cocoon mixed with earth, and remains through the autunm and winter, transforming to pupa the following spring. Shortly afterwards the adult gnaws through the cocoon and works its way up to the surface of the ground. The solitary wasps of the family Crabronidse are rather small insects which burrow in soil and sometimes in decaying wood. A great va- riety of insects is stored in these cells, each spe- cies, however, seeming to have a distinct pref- erence. The industry of some of the members of this family is extraordinary. The Peckhams have observed Crahro stirpicola working night and day for a period of forty-two consecutive hours. The 'mud-daubers,' or mud-wasps, of the genus Sceliphron (formerly Pelopseus) build cells of mud, frequently in great numbers, in sheltered places, often entering houses and barns for the purpose. Spiders are stored in these cells, as a rule, and a single egg is laid upon the last spider which has been pushed in, and the larva works rajiidly. as do other wasps' larvae of this group. The female wasp completes and provisions one cell before beginning another. The sand-wasps of the family OxybeIida» burrow in the sand and provision their nests with flies. A close study of the habits of the solitary wasps by several acute observers has brought out many interesting points bearing upon different theories of instinct, and important contributions to our knowledge of the psychology of insects have been made fiom observations ujion this group. For example, in the genus Annuophila the wasps, carefully cover their burrows when they are completed and stored, taking the great- est care to conceal the entrance, the mother wasp frequently returning from time to time to see that nothing has been disturbed, and adding sand or otlicr disguising substances to the covering of the burrow. The most interesting feature of the habits of these insects, how- ever, is the undoubted use of a tool by the mother in- sect. In filling in the mouth of the burrow, Williston has seen the mother wasp take a stone in lier jaws and use it as a tamping iron to pack the earth down more tiglitly. Fabre's extended studies led to the conclusion that thesc solitary wasps are ins|iired by automatically perfect in- stincts which can never have varied to any great extent from the beginning of lime. In liis opinion devia- tion from regular rule would mean extinction. G. W. and K. (!. Peckham. however, after equally close stiuly, found that variability in the haliits of difVcrent individuals of the same species exists in every particular — shape of nest, manner of digging it. manner of stinging the prey and of crushing it, luaniii'r of carrying tlic victim, way of closing the nest, and even in either closing the nest or leav- ing it open. In the study of the Ammophilas it was especially noticed that there is a very dia- CEI.Ij of a MUn-WASP.