POTENT PERSONALITIES-WASPS AND HORNETS 



65 



villain in the story, the cause of many 

 tragedies. It was a cuckoo wasp (Plate 

 VIII, upper left and top), looking for a 

 chance to place an egg in one of the cells. 

 The grub, emerging from its egg, would 

 have fed upon the baby mud dauber, finally 

 killing it. Many young mud daubers every 

 year are victims of these cuckoo wasps. 



HOW THE BLUE BURGLAR ROBS A HOUSE 



Quite as callous as this jewel-like villain 

 is another wasp, much like the yellow-legged 

 mud dauber, but dark steel-blue in color — 

 the blue burglar (Plate IV, figure IS: Plate 

 VIII, on bottom of cell mass at upper left). 



These steely-blue wasps are habitual 

 housebreakers. After a yellow-legged mud- 

 dauber has built a cell, stocked it with 

 food, and sealed it, one of these burglars 

 comes along, breaks open the cell, throws 

 out the spiders, and proceeds to make itself 

 at home. It cleans out the cell, then stocks 

 it with a new supply of spiders, laying an 

 egg on the last one. Then it seals up the 

 cell in a clumsy and amateurish manner. 



These wasps are common about puddles. 

 But you never see them standing on their 

 heads and digging up the mud. Instead, 

 they fill themselves with water. This they 

 use to moisten the mud of the cell so that 

 they may break it open, and also to soften 

 mud for use in sealing. Sometimes, instead 

 of breaking into fresh cells, they use old 

 ones from which the mud daubers have 

 emerged. 



THE MUD daubers' TENANTS 



Old mud-wasp cells are much in demand, 

 being used by a number of other wasps, 

 some bees, and different kinds of insects. 

 One of the wasps ( Trypoxyloti davatnm, 

 Plate VIII, lower left), being much smaller 

 than the mud dauber, makes two cells out 

 of a single mud-wasp cell by means of a 

 mud partition. 



Both sexes of this little wasp cooperate 

 in home building. But the lady does all 

 the heavy work. Her husband remains al- 

 most entirely within the cell. His duties, 

 as he interprets them, are almost wholly 

 supervisory. 



Another little wasp (Ancistrocerus unci- 

 natiis, Plate VIII, right center) also uses 

 as nurseries the abandoned cells of mud 

 daubers, dividing each into three by mud 

 partitions. In contrast to the others, this 

 wasp stores the cells with caterpillars. 



A third wasp (Pscudagenia adjunct a, 



Plate VIII, upper right) finds these aban- 

 doned cells useful as hiding places for its 

 own mud cells which it constructs within 

 them, storing them with spiders. A few 

 other kinds of wasps also use these cells. 



In addition, some of the mason bees (as 

 Osmia cordata, Plate VIII, lower right) find 

 these cells useful. They divide them into 

 compartments, sometimes as many as five, 

 by partitions of a waxy substance. They 

 then plug the opening with wax. 



Besides the mud dauber many other 

 wasps make cells of mud. One, the com- 

 mon pipe-organ wasp, constructs a num- 

 ber of parallel mud tubes, usually opening 

 downward. After a tube is finished the 

 inner end is packed with food, provided 

 with an egg, and closed with a wall of mud. 

 Then another section is provisioned and 

 closed off in the same way, and the process 

 is repeated until the tube is full, when an- 

 other tube is built beside the first (page SS). 



The most accomplished masons are cer- 

 tain small tropical social wasps (as Polybia 

 jasciata) that build large and very hard 

 mud nests in which even the delicate combs 

 are made of earthenware. 



jug-makers fashion graceful urns 



The most artistically inclined of our com- 

 mon mason wasps are the potter wasps, or 

 jug-makers. On slender twigs or grass 

 stems they construct symmetrical little urns 

 with a narrow neck expanding into a broad, 

 thin, flangelike lip (Plate II, upper). 



After the jug is made, the mother wasp 

 stores it with paralyzed caterpillars, then 

 lays an egg, which is suspended from the 

 top by a slender thread, like a pendulum, 

 and seals it. The young one, after emerg- 

 ing from the egg, consumes the caterpillars. 



In winter you often see these little urns 

 on the bare twigs, usually singly, sometimes 

 two or even three together. Inside each 

 urn is a plump grub, chilled and motionless 

 — dead, apparently. But with the warmth 

 of spring it revives and changes to a pupa. 

 Later the pupa changes to a wasp that bites 

 a hole in the side of its mud prison and 

 comes forth (page 54 and Plate II, lower, 

 female left, male lower center). 



Other wasps related to these jug-makers 

 construct more or less elaborate apartment 

 houses — for children only. These, too, are 

 often seen in winter, when they seem to 

 be nothing but irregular lumps of mud 

 wrapped around a twig (Plate II, upper, 

 right). 



