6 4 6 
THE STUD Y OF INSECTS. 
In breeding these insects from their nests care should be 
taken not to mistake cuckoo-flies or other guest-insects or 
parasites for the rightful owners of the nests. The fact that 
members of each of these classes of insects are common in 
these nests adds both to the complexity and interest of the 
study. 
The digger-wasps found in America north of Mexico 
represent fourteen families. These can be separated by 
the following table: 
TABLE FOR DETERMINING THE FAMILIES OF THE 
SPHECINA.* 
A. Pronotum considerably produced backward on the sides reaching 
the tegulae in the winged forms ; in one family the females are 
wingless. 
B. Abdomen with the first ventral abdominal segment distinctly 
separated from the second by a constriction (Figs. 769, 770). 
C. Intermediate tibiae with two apical spurs; the intermediate 
coxae contiguous, or but little separated ; females wingless. 
p. 648. Mutillidje. 
CC. Intermediate tibiae usually with a single apical spur, very 
rarely with two; intermediate coxae, as a rule, widely sepa¬ 
rated ; both sexes winged, p. 649... .ScOLUDiE, 
BB. First and second ventral abdominal segments not separated 
by a constriction. 
C. Hind legs short, the tibiae not reaching to the apex of the 
abdomen, p. 649. Sapygid>e. 
CC. Hind legs long, the tibiae reaching beyond the apex of the 
abdomen, p. 650.Pompilidje. 
AA. Prothorax usually consisting of little more than a narrow 
collar, the posterior angles not reaching the tegulae; both sexes 
winged in all species. 
B. Fore wings with three closed submarginal cells, (Fig. 773, 2d 
III, Ills, Ilh). 
C. Base of abdomen with a long slender portion (petiolate). 
* This table is based on one given by Mr. Cresson in his Synopsis of the 
Hymenoptera of America north of Mexico, Philadelphia, Am. Ent. Soc., 
1887. 
