80 



ON THE HABITATIONS AND 



that it is hardly discernible, even with the assistance 

 of a powerful microscope ; they are of a horn shape, 

 cylindrical in the middle, with the anterior orifice 

 circular, and the posterior opening of a triangular 

 form. If these habitations were cylindrical through- 

 out, the contraction of them would be an operation 

 requiring comparatively very little mechanical skill ; 

 but, as the two ends are quite different, so there 

 is a necessity for both sides being dissimilar in their 

 curvatures ; and we have the assurance of Reaumur, 

 that they require the same nicety of imitation and 

 junction as the different pieces of which the back of 

 a coat is composed. 



Speaking of insects of this tribe, Mr Spence says, 

 " Their proceedings I had the pleasure of witnessing 

 a short time since upon the alders in the Hull 

 Botanic Garden. More ingenious than their brethren, 

 and willing to save the labour of sewing up two sides 

 in their dwellings, they insinuate themselves near the 

 edge of a leaf instead of in its middle. Here they 

 form their excavation, mining into the very crenatures, 

 between the two surfaces of the leaf, which, being 

 joined together at the edge, there form one seam of 

 the case ; and, from their dentated figure, give it a 

 very singular appearance, not unlike that of some 

 fishes, which have fins on their backs. The opposite 

 side they are necessarily forced to cut and sew up ; 

 but, even in this operation, they shew an ingenuity 

 and contrivance worthy of admiration." 



Those species of T'tneee which excavate their habita- 

 tion in the middle of the leaf, separate entirely the 



