412 Dr. Kidd on tlie Analomij 



of the tibia with the tarsus ; some of which being directed 

 downwards, give tlie insect a firmer hold in walking. 



The hind legs bear a general resemblance to the middle legs ; 

 but the coxa, femur, and tibia, — the femm* especially, — aremuch 

 larger and stronger. The relative position of the parts with re- 

 spect to each other is the same as that of the middle legs; but 

 their general direction, instead of being at right angles to that 

 of the abdomen, is parallel to it. In addition to several sharp 

 spines placed about the joint of the tibia and tarsus, and di- 

 rected downwards as in the middle legs, there are four or five 

 others placed at the back of the tibia near its lower extremity, 

 and pointing slightly downwards. The structure of the tarsus 

 scarcely differs from that of the middle leg. These hind legs 

 are evidently the great instruments of progressive or retro- 

 gi'essive motion. 



TJie xvitigs. — There are two pairs of wings: the upper pair, 

 arising from each side of the first segment of the abdomen, 

 partially cover the lower pair, which arise from each side of 

 the second segment. In several instances I found adhering 

 to the body, in the vicinity of the roots of the wings, a minute 

 parasitic insect of a light scarlet colour : the number of these 

 parasitic insects rarely exceeded eight or ten in the same 

 mole-cricket, but in one instance I counted nearly forty*. 



The upper wings in the full-grown mole-cricket are not 

 above one-fourth the size of the other pair : they are of an 

 oval form and convex externally ; and their nervures or wing- 

 bones, as they are called by Dr. Leach, are remarkably thick 

 and hard. 



The under wings, when expanded, measure full three inches 

 from the outer extremity of one to the corresponding extremity 

 of the other. They may be compared in form to a bivalve 

 sliell, contracted and elongated towards the hinge; at which 

 point is the joint of the wing : from hence, as many as thirty 

 nervures, almost all of which are remarkably delicate, radiate 

 in straight lines to every part of the extremity. A very thin 

 and nearly colourless and transparent membrane forms the 

 medium through which these nervures radiate ; and through- 

 out the whole expanse of the wing these nervures are mutually 

 united by more delicate nervures, which cross at nearly re- 

 gular intervals, and at right angles from one to the other, pre- 

 senting altogether the appearance of a curiously chequered 

 surface. These wings, though so broad when expanded, are 

 scarcely the twelfth of an inch in breadth when folded ; and 

 appear at first view, in this state, any thing but what they 

 really are. They have indeed been often mistaken for a mere 



* Vide Plate II. fig. 5 a. 



caudiform 



