52 
LEAFHOPPEES AFFECTING CEREALS, ETC. 
ovipositor, this latter being a narrow sawlike pair of blades extending 
to the tip, sometimes considerably beyond the tip of the sheaths. 
The males have for the terminal segment beneath a modified segment, 
called the valve, which is followed by two movable pieces called 
plates. Above these, forming the sides of the last segment, are the 
pygofers. A ready understanding of these various parts will be helped 
by a stud}' of the accompanying figure 1, in which they are located 
y 
Fig. 1.— Explanation of terms from drawing of AtJiysanus obtutus: a, Female from beneath; b, from side; c, 
from above; d, female genitalia; e, male genitalia; /, larva or nymph; g, eggs, showing developing larva?; 
h, egg, enlarged; i, eggs in position beneath sheath of grass stem. Structural details: ac, Apical cells; 
aac, anteapical cells; cl, clavus; clyp, clypeus; cox, coxa; fr, front; fern, femur; lora, lora; ov, ovipositor; 
plate, plate; pr, prothorax; py(<f),ry ($), pygofer; tar, tarsus; tib, tibia.; v, vertex; vs, terminal ven- 
tral segment; valve, valve. All enlarged. (After Osborn and Ball.) 
and named. For the different stages of insects the usual terms egg, 
larva, or nymph, pupa, and adult are used, as these are sufficiently 
definite in indicating the steps of development from the egg to the 
mature form. 
THE MORE IMPORTANT SPECIES AFFECTING CULTIVATED CROPS. 
The Yellow-headed Leafhopper. 
(Drxculacephala reticulata Sign.) 
The yellow-headed leafhopper (Drsecvlacepliala reticulata Sign.), 
an extremely abundant species in the southern United States, has 
been noticed a number of times as destructive in wheat or oats, but 
has never received any full discussion, and we are still ignorant 
as to the details of its life history. It was described by Signoret as 
