nine British Species of the Genus Hyleus. 31 
Sp. 4. Hyleus dilatatus. (PI. Il. fig. 1, and details.) 
Black; face pale yellow; mandibles black at the base, then 
yellow, with their apex rufescent. Antenne black above, fulvous 
beneath, the apical segment totally so; the scape remarkably 
dilated, subquadrate, convexo-concave ; the upper half black, 
beneath yellow. Thorax, a yellow spot on the tegule, one on 
each side of the collar, also on the tubercles; tibize yellow, 
anterior and intermediate, with a black stain behind; posterior 
tibiz annulated with black; the wings fuscous. The abdomen 
covered with a fine silvery pubescence, particularly the margins 
of the segments. 
Length, 3 lin. 
This species is an astonishing instance of what almost appears 
disproportionate enlargement. The scape of its antenna, says 
Mr. Kirby, resembles a “ patella,” or deep dish; but if viewed on 
its concave side, it certainly bears a striking resemblance to an 
ear; and although I would not boldly declare, with a learned 
professor, ‘these are its ears,” still I consider them admirably 
adapted for collecting the vibrations of sound. Immediately be- 
hind the concavity of the scape, on the face of the insect, is a 
longitudinal smooth depression, extending to its outer margin, so 
that a passage for the vibrations of sound (should such a mecha- 
nical apparatus be the intention as I have described) is here 
admirably executed. I have examined the concavity under a 
Codrington lens, and find it perfectly smooth ; not the slightest 
indication of any aperture or communication either with the joints 
of the antennze, or where the scape inosculates with the head. I 
have drawn a figure of the insects, as well as an outline of the 
face, and concave side of the scape. This species appears to be 
rare. I am indebted to Mr. Samuel Stevens for my specimen, 
captured in Sussex. 
Sp. 5. Hyleus pallidens, Kirby’s MSS. 
Male.—Black ; scape of the antenne with a yellow line in 
front; face white; the mandibles yellow. Thorax more pubes- 
cent than in the other species, particularly beneath; anterior tibiz 
yellow, with a brown stain behind ; the femora with a yellow line 
in front; intermediate and posterior tibiz yellow at their base ; 
all the plantz yellow; remaining joints of the tarsi pale ; claws 
rufous; wings fuscous. Abdomen piceous, with a fringe of white 
hair on each side of the first segment. 
Length, 3 lin. 
