1884. ] Recent Literature. 1239 
nena which connects them with the rim of the furrow-plate. 
“a below this fork an unpaired piece (sd) connects it with 
the inferior fork, and sends backwards a hook-like process. 
ieh oem membrane, which is continuous with the margins of 
. e labial plate, enlarges distally and swells out so as to consti- 
= ~ = large terminal labellar cushions of the disti-probos- 
een e peer condition these lie with two flat surfaces 
“ A ea ve they have each an inner and an. outer surface. 
_ s r the lower forks support the outer cushion-walls. 
8 0 orks, whose limbs run parallel, support the inner sur- 
tell e cushions. Between these supporting bars the thin 
nah . # sculptured in a special way. Each branch of the 
x r fork has, from its place of articulation with the furrow- 
plate, a chitin-arc running longitudinally (Fig. 7, ca); between 
t o%& 
T > Hy Phic s a 
FIN a A 
ANKAA NRES 
Fig. 7.—Side view of labium. 
these arcs the membrane is extended The membrane has radial 
folds in bas-relief, soon rising to high relief, forms which depend 
on secondary foldings of the membrane, called by Macloskie and 
Dimmock “scraping teeth” or spines (Fig. 7, 4). There are 
three rows of such spines, the second and third rows being fold- 
ings external to those of the order next below. These are suc- 
ceeded by foldings of a fourth order which, instead of forming 
teeth, bend round as semicircular bars and form the beginnings 
of the often described pseudo-trachee (#ż). The supporting 
arches thus have (morphologically) the same origin as the teeth. 
On the outer rim, where outer and inner walls merge, the pseudo- 
trachee, after diminishing distally, terminate. There are also 
“oe supporting rods between the pseudo-trachee (Fig. 
» S7). 
ionally two rows of teeth.—G. M. 
. Í may add to the above that the 
crenulate with deep sinus between the 
Hes (AMER 1 p. I 
ae by the simple extremity of one arc, and at its two r 
ba joining arcs; so that the deep sinus n is bounded by the 
alis ed end of an arc. The fine membrane between the pseudo-tracheæ is hexagon- 
y areolate, like the facets of the eyes, the areoles having sunken boundaries 
mh may flatten out when the labellz are expanded). My observations are from 
e housefly. —G. M. 3 
