200 Mr. C. H. Goodman’s Notes on the House-cricket. 
insect with a pin it will be noticed that when raised vertically 
the base of the large joint forms the hinge, but if laterally, the 
movement starts from the apex. I can find no trace of ocelli, 
though there are three conspicuous white marks near where we 
should expect to find them. 
Trophi.—The mouths of all biting insects consist of two pairs 
of jaws working laterally, and an upper and lower lip. The 
mandibles, or upper pair, are here seen to be strong biting in- 
struments, and it is interesting to notice that in this case they 
are unsymmetrical. Nothing seems to come amiss to crickets ; 
they have been seen to drag cockroaches from their holes and 
devour them, and even eat boots and shoes, or their own dead 
companions. They also use the mandibles for excavating retreats. 
Below the mandibles are the maxille with their palpi, the labium 
or lower lip with its labial palpi, and also what are largely de- 
veloped in the crickets, the galee; and, lastly, the paraglosse, 
which appear like a third pair of jaws. Connected with the 
labium is the ligula or tongue. In its natural position this is in 
the mouth, and forming a hollow fleshy eminence, but when 
pressed out, as in the illustration, it is seen to be kidney-shaped, 
with radiating fibres. In common with other biting or man- 
dibulate insects, they are provided with a gizzard, the teeth of 
which serve to triturate their food. 
The prothorax carries the anterior legs, and it is to the tibix 
that our interest is most directed, as here are found the organs 
of hearing, though this sense is probably partly served by the 
antenne as well. Near the middle on the outer side we observe 
an oval, smooth, glassy disc, while on the inner and opposite 
side a similar small circular one can be detected. These tympana 
have enlarged trachez and numerous nerves in their immediate 
neighbourhood, and that this is their office may be inferred from 
the fact that species without stridulating apparatus are usually 
also destitute of these tympana. 
Elytra.—The mesothorax carries the elytra and intermediate 
pair of legs. In the female the elytra present no specially 
noticeable feature. They lie horizontaliy on the back of the 
insect, with the outer margin turned down. On turning to the 
male, however, two or three clear smooth spaces will be seen 
surrounded by strong nervures. These tympana or drums act 
as sound-boards, while underneath, about a third from the base, 
can be traced a ridge of fine teeth running half across the 
elytron, and then turned upward. These teeth form part of the 
stridulating apparatus, which is possessed by the male insect 
only. The broad edges of the teeth are somewhat produced at the 
angles, and there are all together about 230 in number. When 
the elytra are at rest they overlap each other, and out of twenty- 
four mature specimens I examined in ten males and nine females 
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