40 OUTLINES OP ENTOMOLOGY. 



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ever, burrow into the earth, especially in sandy or gravelly situations, 

 loosening the soil with their strong jaws and scrabbling it out with 

 incredible rapidity with their spiny legs. 



A separate hole is dug, six or seven or more inches deep, for each 

 egg, at the bottom of which the latter is laid, after the nest has been 

 provisioned with one large or several smaller insects or spiders reduced 

 to torpor by the poisoned lance of the wasp. The shaft is then filled 

 up, the earth smoothed over, and even bits of gravel so placed as to 

 completely obliterate all trace of the excavation. 



The Wood wasps (family Crabronid^), which bore into wood, feed 

 their larva; on plant lice, a great number of these tiny insects being 

 required to provision a single cell. Species of the genus AmmopMla — 

 easily recognized by the very spiny legs and the long, slender pedicel 

 gradually widening backward into the rather small abdomen— provide 

 each nest with but one large caterpillar. 



The elegant wasp known as the ''Handsome Digger" fStisiis specio- 

 stis, Drury), represented in Fig. 15, a very large species of a black color 

 gaily banded and otherwise marked with yellow, provisions its nest 

 with harvest flies (Cicadas), making use of the seventeen-year species 

 when they appear, as well as of the annual "drummers." A still larger 

 species fPonipilus formosus, Say), of a dark blue color, common in the 

 Southwestern States, is called the "Tarantula- killer," because it makes 

 the large and venemous Tarantula, the most formidable of our spiders, 

 its especial prey. The Digger wasps are a great terror to the insects 

 upon which they prey, the latter seeming to recognize them instinct- 

 ively as enemies from which there is no escape. Observers have no- 

 ticed that even the Tarantula above mentioned, large and savage as it 

 is, is seized with a violent tremor and appears to lose all courage as 

 soon as it finds itself pursued by the fierce Fompilus. 



A small black wasp belonging in the genus Tiphia, common in the 

 north and west, is distinguished as one of the few insect enemies of 

 the destructive White grub, its tough, brown, silken cocoons being 

 frequently turned out by the plow in the spring from meadows and 

 corn land. 



All wasps, whether social or solitary, may be considered among 

 beneficial species, for although the perfect insects feed only on honey 

 and pollen, yet in providing for their young they destroy vast numbers 

 of leaf and fruit- feeding larv?e as well as various grasshoppers, cicadas 

 and flies. In preparing these insects to nourish their young the attend- 

 ing wasps of the social species thoroughly masticate and partly digest 

 them before they regurgitate the pulp into the open mouths of the 

 larvse. The Solitary species, as we have seen, have a provision for 



