408 Trans. Acad. Sci. of St. Louis 
sect World, p. 198. 1907); 7. tridentatum uses the pith 
chamber of elder twigs (Rau, Wasp Studies Afield, p. 
134) ; T. collinum Sm. was seen to enter a burrow prob- 
ably made by some other insect in hard sand (Ashmead, 
Psyche 7: 45. 1896); T. attenuatum emerged from per- 
forated bramble stems (Saunders, Trans. Ent. Soe. 
Lond. 1880. p. 278); T. clavicernwm nests in posts (Mor- 
ley, Entom. 31: 14, 1898) and inhabits galls of Cynips 
kollari (Billups, Entom. 28: 47. 1895); 7. rubrocinctum 
and 7. albopilosum nest in posts (Peckhams, Psyche 7: 
303. 1895), and T. rubrocinctum was found in an elder 
stem (Rau, Trans. Acad. Sci. St. Louis 24:22. 1922); T. 
corinifrons takes up its abode in round holes made by 
Scolytids in pine timber (Ashmead, Psyche 7: 45. 1891) ; 
T’. texense occupies small crevices in wooden or stone 
walls, beetle holes in cedar posts, unoccupied cells of old 
mud-daubers nests, holes mechanically bored in blocks 
of wood, and empty shot-gun shells standing upright 
(Hartman, Bull Univ. Tex, 65: 57-60. 1905); and in clay 
banks, using tunnels dug by bees (Hungerford and Wil- 
liams, Ent. News 23: 248-249. pl. 16); T. cockerellae re- 
sides in the old nests of the mud-daubing wasps (Rau, 
Journ. Anim. Behav. 6: 36-42. 1916); T. rufozonale was 
dug from its nest, a hole in a clay bank, (Smith, Univ. 
Nebr. Stud. 8: 30. 1908); 7. rejector builds its own cells 
and is also in the habit of appropriating those of other 
insects (Horne, quoted in Wood, Insects Abroad, p. 477) ; 
I. alternatwm uses stems of roses and brambles, the 
cells separated by walls of sand (Wood, Insects Abroad, 
p. 477); T. scutifrons and T. errans were induced to 
make their cells in glass tubes (Wheeler, Sci. Monthly 
25: 86. 1922); T. figulus uses galleries she does not her- 
self dig (Fabre, Bramble Bees and Others, p. 102. 1915); 
T. excavatum Sm. nests in stems of syringa (Rohwer, 
