Wasps 



Mr. F. H. Chittenden tells me that he thinks one of these 

 Polistes wasps was responsible for the destruction of the cabbage 

 caterpillars in the center of a large cabbage field near Washington 

 last summer. The wasps would hover about a plant and then 

 alight and walk about it, but finding nothing would continue to 

 the next plant, and so on to the next. In the sunny center part 

 of the field the cabbage caterpillars were exterminated, but in the 

 shady portions next a patch of woods they were present in great 

 numbers. Wasps do not see well. They find their prey more 

 by a sense of touch than by a sense of sight, and as they prefer 

 the sunshine they unconsciously ignored the abundant caterpillars 

 in the shade. 



There are tropical social wasps, most of them belonging to 

 the genus Polybia, which build enormous nests. It is said that 

 the nest of a Ceylonese wasp reaches a length of six feet, and 

 with a common South American form the paper is so thick and 

 hard that it resembles thick pasteboard, while the outer layer is 

 so fine in texture that one can readily write upon it with ink and 

 a fine pen. 



The solitary wasps of this super-family, although differing in 

 structure, resemble greatly in habits the solitary wasps of the 

 super-family Sphegoidea. There is one large family known as 

 Pompilidae, of which we have many representatives in this coun- 

 try. All of these wasps whose habits are known prey upon 

 spiders. More than a hundred species occur in the United States, 

 and most of them dig burrows in the ground, some of them, 

 however, using readily natural burrows and those of other 

 insects. Some of them dig their burrows before they catch their 

 spiders, and others catch the spiders first; and one species has 

 been seen to carefully hang its spider on the branch of a plant 

 where it would not be disturbed by ants while the burrow was 

 being made, occasionally visiting it in the intervals of work to 

 find out whether it was safe. The habits of several Pompilids 

 have been studied by Mr. and Mrs. Peckham. There is a famous 

 wasp of this family which in the Southwest is known as the 

 tarantula-killer. 



The wasps 01 the family Eumenidae are known as potter- 

 wasps, and store up caterpillars, saw-fly larvae, and the larvae 

 of beetles. They form globular cells of clay or sand which are 

 attached by a small pedestal to some twig. They are filled full 



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