132 THE PERIODICAL CICADA, 
within the egg period of seven or eight weeks of the Cicada, and this 
accounts for its excessive multiplication, as described by Mr. Hart- 
man, and probably makes it wherever it occurs one of the most 
efficient agencies in keeping the Cicada in check. 
THE LARGER DIGGER WASP. 
I have already referred to the probability of the larger digger wasp 
(Sphecius svneciosus Dru.) preying on belated individuals of the period- 
ical Cicada. That 
the bulk of the 
brood has disap- 
peared, however, 
before this wasp 
becomes at all 
abundant has 
been often pointed 
out and is not to 
be questioned, and 
Fig. 57.—Cicada in burrow of Sphecius, with full-grown larva of latter it is well known 
feeding. Natural size (after Riley). hat the toast ae 
its work is with the later-appearing dog-day harvest fly (Cicada 
tibicen Li.). With the assistance of Mr. Pergande and the writer, Pro- 
fessor Riley worked out the natural history of this wasp in detail in 
its relation to the dog-day harvest fly, and published a full illus- 
Fig. 58.—Sphecius speciosus: a, larva; b, pupa, from below; c, same, from side, natural size; e, head 
of larva; f, labium of same; g, maxilla of same. Enlarged (after Riley). 
trated account of the species.? Its life habits when it preys on the 
periodical Cicada are identical with its habits with the dog-day 
species or any other annual Cicada with which it may store its bur- 
rows. <A brief account of the habits of this wasp is here reproduced, 
together with the figures illustrating its very curious and interesting 
life stages. (See figs. 54-60.) 
a Insect Life, Vol. IV, March, 1892, pp. 248-252. 
