TRUE ORTHOPTERA 3145 



venation to green leaves; while in others they look more like withered leaves. 

 Nowhere is this style of protective coloration better displayed than in the exotic 

 genera Cycloptera and Pterochroza, one of the species of which is figured in the 

 colored plate. The shape, color, and venation of the wings are not only exactly 

 like those of leaves, but there may be seen, here and there, little glistening, trans- 

 parent patches of cuticle, which reveal, as it were, the work of an insect grub. In 

 others, fungi seem to grow on the leaves, and leave their mark in the discolored 

 patches which may be seen scattered about. Among the species of the family 

 remarkable in other respects we have space to mention only a few. In the genus 

 Hetrodes the adult insects of both sexes are without wings; the prothorax 

 is very large, and is armed above with a number of spines. An idea of the gen- 

 eral appearance of the adult insect may be gathered from the figure of Hetrodes 

 spinulosus. This species is found in Arabia and Syria. For the sake of contrast 

 the male and female of a small British grasshopper (Meconema varium) are figured 

 beside it. The latter is winged in both sexes; it is found in oak trees, and belongs 

 to a subfamily which is peculiar from the fact that the elytra of the male have no 

 stridulating organs. 



The locusts and short-horned grasshoppers (Acrtdnda) are distin- 

 guished by easily recognized characteristics from the other two families 

 of the suborder. The antennae are short, seldom attaining more than half the length 

 of the body, the tarsi are three jointed, and the female always has a very short 

 ovipositor. They differ also in the position of the auditory organs, and in the 

 mode by which the males produce the chirping. In these insects the organs of 

 hearing appear externally as two pits, somewhat crescentic or semilunar in shape, 

 placed one on each side of the first abdominal segment, immediately behind the 

 thorax. At the bottom of each pit there is a tense membrane, which on its inner 

 side is brought into relation with the terminal rods and fibres of a nerve which 

 arises from the last thoracic ganglion. It was thought that these pits were in some 

 way concerned in the production of sound, but it is evident from their structure 

 that this is not the case, while they really seem capable of serving no other function 

 than that of ears. Moreover, it is now known that the chirping of these insects is 

 produced by rubbing the hind-legs up and down against some of the projecting 

 nervures in the sides of the closed elytra. When the insect is stridulating it keeps 

 the tibia of the leg folded up against the femur. In some species the sound is 

 heard at both the upward and downward stroke of the legs, in others at the down- 

 ward stroke only. The sound varies in intensity in different species, and for this 

 reason some of the commoner species may be recognized even before they are seen. 

 In most of these insects the front of the head is vertical, or slightly inclined back- 

 ward, but in some ( Tryxalince) it is much inclined backward, and the whole head 

 seems prolonged in a way that makes it look like a cone or wedge, with the 

 antennae and eyes near the apex, and the mouth placed below under its base. The 

 Acridiidce are usually provided with three ocelli in addition to the compound eyes, 

 the ocelli being as a rule more distinct than in the Locustidce. The mouth organs 

 are well developed, consisting of a large upper lip; strong, toothed masticatory jaws; 

 five-jointed maxillary palpi; and a lower lip, divided at the end into two or four 



