1964] 
Evans — Nesting behavior 
147 
lists of prey taken by P. solivagus, politus , gibbosus , and bilunatus 
(Evans and Lin, 1959 ). The complete list follows (determinations 
made by myself, using the keys in Mitchell, i 960 , in connection with 
specimens determined by Mitchell) : 
Species of prey 
Andrenidae 
Pseudopanurgus andrenoides (Smith) 
HiALICTIDAE 
Augochlora pur a (Say) 
Augochlorella striata (Provancher) 
Dialictus apertus (Sandhouse) 
D. cressonii (Robertson) 
D. inconspicuus (Smith) 
D. laevissimus (Smith) 
D. tegularis (Robertson) 
D. vers arts (Lovell) 
D. spp. 
Evylaeus divergenoides Mitchell 
E. macoupensis (Robertson) 
Halictus ligatus Say 
Total 
Number taken 
Granby Center, Lexington, 
N. Y. Mass. 
1 
$ 
2 
8 8 
1 
2, 3 
8 8 
1 
2 , 
1 
8 
1 
8 
1 
2 , 
6 
8 8 
16 
2 2 , 
1 
8 
10 
8 8 
7 
$ $ 
3 
8 8 
1 
2 
1 
?, 2 
8 8 
5 
8 8 
3 
8 8 
2 
8 8 
1 
2 
3 
$ $, 15 
8 8 
27 
2 $, 
24 
8 8 
Parasites. — Parasitic flies were much in evidence in both localities. 
In both areas several of the flies were captured as they pursued fe- 
males laden with prey; all were determined by C. W. Sabrosky as 
members of the Senotainia trilineata complex (Sarcophagidae: 
Miltogramminae) . Members of this complex are known to attack 
a wide variety of ground-nesting wasps. None of the six cells exca- 
vated contained maggots, and no maggots were noted on any of the 
bees found in storage in the burrows. 
Provisioning females being pursued by Senotainia undertake a 
characteristic flight, hovering near the nest or flying slowly forward 
3-6 cm high, sometimes to a distance of several meters from the nest. 
The fly usually follows just behind the wasp and slightly below. If 
unable to rid herself of the fly, the wasp may fly rapidly and deviously 
and may leave the area altogether, to return a few moments later, 
usually without the fly. Presumably the flies larviposit successfully 
on the prey at times, as described in the case of P. solivagus and 
these same flies by Ristich ( 1956 ), but I observed no cases of suc- 
cessful larviposition and, as already mentioned, found no maggots in 
the few nests excavated. 
In Lexington, the mutillid D asymutilla nigripes was very common. 
On several occasions females were seen entering the open false 
burrows, digging a bit, and then leaving. None were seen entering 
