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The Sceliphronini or mud-daubers make up a very cosmopolitan 
group and are the familiar thread-waisted wasps often seen at 
wayside puddles, where they gather mud for nest-building. All, 
as far as known, prey on spiders. The nests of the Sceliphronini 
are more or less characteristic in the size, shape of cells, etc., for 
each species. While the common metallic blue Chalybion caero- 
leum of America makes entire cells of mud, her equally abundant 
sister C. violaceum of the Old World seems merely to plug up 
ready-made cavities. Maindron (1878), in speaking of Sceliphron 
laetus in the Moluccas, says that in building a cell the insect leaves 
both ends open until the last, so that she may the more readily 
enter and leave it; he adds that the wasp passes the night in one of 
the cells. This is an unusual procedure for insects of this group, 
which are commonly recorded as sleeping some distance from 
their nests. 
The spiders which these mud-daubers capture are relatively 
small and easily handled; sometimes they are stung to death, and 
in other cases paralyzed. I once saw a Sceliphron caementarium 
in Hawaii suspended from a leaf by her two hind legs while with 
the other four she held an attid or jumping spider, and, bending 
her abdomen forward, stung her captive on the underside (the 
side facing her body) of the body. 
The genus Podium of the American tropics is related to Sceli- 
phron and is likewise a mud-dauber of the household as well as 
of the forest, but stores her cells with small cockroaches (Howes 
1917). 
The genus Ammophilay comprises slender digger wasps, of 
interest “because of the care and precision with which they sting 
and paralyze their caterpillar victims, and are remarkable for 
other nesting instincts. 
The genus Chlorion with its subgenera includes some hand- 
some wasps of stout build, many exceeding an inch in length. 
They are familiar the world over, and although frequently loud 
and threatening in their actions and sometimes nesting in large 
colonies, never attack one. The Philippine species, of which I 
collected eight, have much the same habits as their relatives in 
other parts of the globe; they store their nests, commonly one- 
celled burrows, with paralyzed locusts, grasshoppers or crickets. 
Different Chlorion species usually have somewhat different nest 
burrows. Thus C. aurulentus var. ferrugineus is the most do- 
mestic and fearless of the lot, and digs her short tunnels next her 
neighbor’s under the shelter of eaves, buildings, etc., and even 
deigns to hunt her prey in Nipa houses; C. umbrosus var. plumi- 

+ Now referred to as Sphex. 
