Bulletin, Tt?e Periodical Cicada, published by the United States Bureau of Entomology in I9O 7 . Doctor Marlatt describes six immature stages of the periodical cicada between the egg and the adult. The young cicada that first enters the ground is a minute, soft-bodied, pale-skinned creature about a twelfth of an inch in length (Fig. 126). The body is cylindrical and is supported on two pairs of legs, the front legs being the digging organs; the somewhat elongate head bears a pair of small dark eyes and two slender, jointed antennae. At no stage has the cicada _jaws like those of the grass- hopper; it is a sucking insect, related to the aphids, and is provided with a beak arising from the under surface of the head, but when not in use the beak is turned back- ward between the bases of the front legs. Throughout the period of its underground life, the cicada subsists on the sap of roots. During more than a vear the young cicada retains ap- proximately the form it'has at hatching, though the body changes somewhat in shape, principally by an increase in the size of the abdomen (Fig. 1?3). According to Doctor Marlatt, a nymph of the seventeen-year race first
Fro. 113. Nymph of the periodi- cal cicada in the first stage, about ? 8 months old, enlarged ? 5 rimes. (From Marlatt)
sheds its skin, or molts, some- rime during the first two or three months of the second vear of its lire. In its second stage it be- comes a little larger and is marked by a change in the structure of the front legs, the terminal foot part of each being reduced to a mere spur and the fourth section being developed into
a strong, sharp-pointed pick which forms a more efficient organ for digging. The second stage lasts nearly two years; then the creature molts again and enters its th}rd
1861
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