Transverse frozen sections from a series taken through the right half of the thorax of <i>Philaenus</i> at the planes indicated in <b>Figure 1D</b> and viewed from their anterior surfaces.

<p>Dorsal is to the top and ventral to the bottom of each image. A. Superimposed images of the same sections taken with UV and with bright field illumination. Intense blue fluorescence occurs in the pleural arch (energy store) within the thorax. Weaker blue fluorescence is present in the exoskeleton. B. The same sections in which antibody labelling is superimposed on the bright field image. The immuno-signal is restricted to the fluorescent regions with a much weaker signal in parts of the exoskeleton.</p

Combined fluorescence and antibody staining of the pleural arches (energy stores) in transverse sections of the thorax of <i>Delphacodes</i>.

<p>Combined images of bright field and UV fluorescence are shown on the left and of UV fluorescence and antibody labelling on the right.</p

Preadsorption controls to show the specificity of the antibody.

<p>A. Transverse section of the thorax of <i>Philaenus</i> illuminated with bright field and UV light. Blue fluorescence is restricted to the pleural arch (energy store). The large muscles that power depression of the hind legs in jumping occupy most of the volume of the thorax. B. Incubation in the antibody after preadsorption with the antigen now fails to label the pleural arch. Only some weak immunolabelling is still present in the exoskeleton.</p

Location of the thoracic energy stores in the pleural arch.

<p>A. Cartoon of the froghopper <i>Philaenus</i> as viewed from the side. B. Ventral view of the posterior part of the thorax of <i>Philaenus</i>. The right hind leg is shown partly depressed and the left hind leg levated with its femoro-tibial joint between the ventral surface of the body and the femur of the left middle leg, held as in preparation for a jump. C. Ventral view of the right half of the metathorax of <i>Philaenus</i> (area indicated by box in B) dissected to reveal the massive pleural arch (tinted grey-blue) which with its counterpart on the other side of the body forms the energy store for jumping. D. Photograph of a ventral view of the metathorax of <i>Delphacodes</i> in which images illuminated with white and UV light have been superimposed to show the blue fluorescence of the pleural arches. The horizontal lines indicate the region from which the transverse sections shown in subsequent figures were taken.</p