MIOPTEEIGES. 161 



nearly filiform. In normal cases (Tab. X. fig. 9) the anterior legs bear on their outer 

 margin five, and on their inner margin a variable number of spines (the subapical spine 

 of each margin is generally distinct), and the discoidal spines are four in number; 

 but the latter are sometimes difficult to distinguish from the other spines, when the 

 femora become much compressed. The femora, when short, are triangular, of normal 

 form and armature: when elongated, the spines are almost confined to the distal, or 

 even to the apical, part of these organs ; in this case they lose some of their spines, 

 the space being inadequate for the development of the whole of these — that is, to 

 allow sufficient room between each for them to act as separate claspers. The proximal 

 part of the femora when without spines has its inner edge finely crenulated by a line 

 of small granules. 



The length of the tibiae varies inversely as that of the femora, the long femora being 

 too weak to assist the clasping action of the long tibiae at their extremity. In the 

 most slender forms the tibiae are so shortened as to become almost rudimentary. 

 This modification is very striking in Oligonyx and Thesprotia. In these types the 

 shortness of the tibiae causes them to lose most of their spines, and those which remain 

 are partly transferred to the extremity of the organ ; it thus happens that as there 

 is no room for one or two apical spines on the inner margin, they are forced 

 upwards and inserted over the last spine of the margin (Tab. IX. figg. 21, 28 ; 

 Tab. X. fig. 24), or even on the dorsal face of the tibiae (Tab. X. figg. 7, 8). Do 

 these spines thus become useless 1 



When the tibiae are very short they cannot be opposed to the femora ; they are, so to 

 speak, reduced to their claw, and it is the claw which alone presses the prey against 

 the spines of the femur. As the claw does not reach beyond the middle of the arma- 

 ture of the femur, the prey can only be caught between the claw and the smaller spines 

 which occupy the end of the femur, and seems to escape the long spines at the base 

 (Tab. X. fig. 9). But it may be presumed that, if caught, the struggling prey must 

 fatally impale itself on these spines by its own movements. It is therefore probable 

 that for this purpose the species with short tibiae have some of the discoidal and basal 

 spines very long and perpendicular. 



The conclusion to be drawn from this organization is that the elongate Miopteriges, 

 and perhaps also the other allied species, hunt very small prey only, probably soft 

 insects. 



The species of the Old World which have been referred to Miopteryx, and also those 

 of allied genera (as Parathespis, Sss., and Hoplocorypha, St.), do not belong to the 

 group Miopteriges. They constitute a parallel series similar in form, but with 

 glabrous wings and feet. 



The following conspectus will help to distinguish the genera : — 



biol. centk.-amer., Orthopt., April 1894. Yy 



