Transactions Texas Academy of Science. 
81 
liquely down and ending in a dilation or pocket at the lower end of 
greater or lesser diameter (Figs. 19 and 21.) Among the mud- 
plastering wasps we may distinguish two methods of work again: 
Some species build the entire nest of mud, as for example Agenia, 
Pelopaeus , while others occupy convenient crevices, and use the mud- 
mortar merely to close the mouth of their ready made nests, as ob- 
tains in the case of Trypoxylon. The same genus may have species 
some of which practice the one, some the other method ( Odynerus, 
Chap. I). And again the same species, as Agenia subcorticalis 
seems to do, may combine the two methods, for she builds complete 
cells of mud not in the open air like Pelopatus but hidden away # 
in crevices. 
Some wasps always carry their prey on the wing and on their re- 
turn to the nest alight directly in or over its entrance. Bembex , 
Monedula, Bembidula , Hoplisoides , Microbembex carry their prey 
with their middle pair of legs and press it closely to their venter; 
RJiopaJum abdominale and Notoglossa use their hind pair; Ody- 
nerus , Trypoxylon and Cerceris carry theirs with their mandibles 
as does also Alyson, which alights some distance from the west and 
completes her journey on foot. Larra americana and Microbembex 
prefer flying to walking; but when the weight is great the advance 
is in jumps or short flights, the distance of each advance being in- 
versely proportionate to the weight of the burden. 
Other wasps always drag the victim over the ground regardless 
of how light this may be and how absurd it may look (to us). Am- 
rnophila/s method, to which that of Priononyx corresponds, is shown 
in Fig. 16. Some spider catchers ( Miscophus , Agenia) walk for- 
ward in dragging their prey; others (some species of Pompilus and 
Pompilogaster) always walk backward. Agenia and some others 
combine the flying and the walking means of progression. These 
drag their victims over the ground, climb up the stems of herbs and 
bushes in their path and fly off, parachute-fashion, from the highest 
point obtainable in the direction of their course. The species dif- 
fer greatly, too, in the ease or reluctance with which they betray the 
locality of their nest, Miscophus and Tachytes ab ductus being, for 
example, experts in leading the observer astray. 
By the way in which a wasp enters the nest the species may often 
be recognized. Bembecids as a rule, after having opened the nest 
and on entering it, head foremost, deftly pass their prey back from 
the middle to the hind pair of legs. Microbembex , for example, 
never fails to do this regardless of the size, weight, or shape of the 
prey. Ammophila, like Priononyx Thomae, lays her victim down 
