ORTHOPTERA 



261 



to these insects; they are also known as stick-insects. In some 

 exotic species the body has the appearance of being covered with 

 moss or with lichens, which increases the resemblance to a stick 

 or a piece of bark. 



While our species are all wingless, except Aplopus mayeri, found 

 in southern Florida, many exotic species are furnished with wings; 

 and with some of these the wings resemble leaves. Among the 

 more remarkable of the leaf-insects, as they are known, are those 

 of the genus Phyllium (Fig. 296), the members of which occur in 

 the tropical regions of the Old World. 



In the walking-sticks, the body is elongate and subcylindrical, 

 the abdomen consists of ten segments, but the basal segment is 

 small and usually coalesced with the metathorax and sometimes it 

 is entirely invisible; the legs are all fitted for walking, the tarsi 

 are five-jointed except in the genus Timema, where they are three- 

 jointed; the cerci are without joints. 



These insects are strictly herbivorous ; 

 they are slow in their motions, and often 

 remain quiet for a long time in one place. 

 They evidently depend on their mimetic 

 form for protection. In addition to this 

 some species have the power of ejecting a 

 stinking fluid, which is said to be very 

 acrid ; this fluid comes from glands placed 

 in the thorax. 



The eggs are scattered on the ground 

 beneath the plants upon which the insects 

 feed, the female, unlike most Orthoptera, 

 making no provision for their safety. In 

 our common northern species the eggs are 

 dropped late in the summer and do not 

 hatch till the following spring, and they 

 often remain till the second spring before 

 they hatch. 



About 600 species of phasmids have 

 been described; but they are largely 

 restricted to the tropical and subtropical 

 regions. Caudell ('03) in his monograph 

 of the species of the United States enu- 

 merates sixteen species that occur in our 

 fauna; but these are foimd chiefly in the 

 southern part of the coimtry. 



Our common northern walking-stick 

 is Diapheromera femordta (Fig. 295). The 

 range of this species extends into Canada. 

 It is a quite common insect, and on sev- 

 eral occasions has appeared in such great 

 numbers as to be seriously destructive to 

 the foliage of forest trees; but these outbreaks have been temporary. 



Fig. 295. — Diapheromera fern 

 orata. 



