142 THE INSECT WORLD. 



segments. The step is thus made, the caterpillar making the same 

 movements in taking the second and following steps. 



This sort of gait has gained for them the name of Geometers, 

 because they seem to measure the road over which they travel. 

 When they make a step, they apply the part of their body which 

 they have just curved up to the ground, in exactly the same way as 

 a land surveyor applies his chain to it. 



These looper caterpillars cannot shorten nor lengthen their seg- 

 ments at will, as other caterpillars, but only bend their bodies. 



Fig. loo. Caterpillar of the Canary-shouldered Thorn (Evgotiia alniaria). 



There are many species whose bodies are cylindrical, stiff, and of the 

 same colour as bark. Their attitudes deceive even the close observer. 

 They embrace the stem of a leaf or twig with their hinder and 

 intermediate legs, whilst the rest of their body, vertically elevated, 

 remains stiff and immovable for hours together. Fig. 100 shows the 

 caterpillar of the Canary-shouldered Thorn (Eugenia alniaria} in this 

 strange position. Now, this is a feat of strength which the most 

 skilful of our acrobats, ordinary and extraordinary, which all the 

 Leotards of the present day, and those who are to succeed-them, can 

 never accomplish. With such a persistency, this caterpillar can 



