A NEW INSECT PRODUCT 69 



it is irregular, hard, and has an amylaceous appearance. It cracks 

 when bitten, has a sweet taste, and yields mucilage. In water, at the 

 ordinary temperature, the trehala swells, but only partially dissolves, and 

 changes into a mucilaginous mass. Iodine changes it to a blue colour, and 

 in some cases to that of red wine. Analysis shows that it contains gum, 

 a particular kind of starch which is much less soluble in water than that 

 from the potato, and a new kind of crystallisable sugar, analogous to that 

 from the sugar-cane, but much more solid : M. Berthelot has given this the 

 name of trehalose. It is during the larval stage of its existence that the 

 Larinus subrugosus constructs this curious kind of case. Does the trehala 

 result solely from a wound inflicted by the insect ? Is it an excrescence 

 similar to the galls produced by the Cynipidie, and to the cases of the 

 Aphides ? Or is it a nest which is made by the Larinus? M. Guibourt 

 admits the second mode as the way in which it is formed. A circum- 

 stance which supports this opinion, is the fact that the trehala is not 

 attached by a point or pedicle like the galls, but is fixed along its whole 

 length by the groove which embraces the point of support. It appears 

 that the larva of the Larinus collects a considerable quantity of saccharine 

 and amylaceous matter, which it procures from the ecliinops, and that it 

 constructs its dwelling by disgorging this matter and moulding it with its 

 rostrum. M. Bourlier thinks that the formation of the sugar which is 

 found in the case might be exjalained by the presence of albuminous 

 matters in the saliva with which the insect binds together the starchy 

 materials. Brother Auge and M. Guibourt think that the nest serves the 

 Larinus for a habitation during the whole of its life : I am, however, 

 inclined to believe, with M. Bourlier, that the insect emerges after it has 

 assumed its perfect form. If it were otherwise, how could copulation take 

 place, since each case contains only one individual? Moreover, most of 

 the nests which I have examined were pierced at one end, and were empty. 

 The trehalas are generally collected before the animal has escaped. In 

 Turkey and Syria, a decoction is made of the nests of the Larinus, by 

 breaking up about an ounce of them, placing the pieces in a pint and a 

 half of boiling water, and stirring them for a quarter of an hour. This 

 preparation is given to persons in affections of the respiratory organs, 

 particularly those who are attacked with bronchitis. The trehala is also 

 employed as food. The use of it is as universal in the East as that of salep 

 and tapioca is in France. 



A closely-allied insect, the Larinus odontalgicus of Dejean, out of which 

 the genus Rhinocellus has been formed, has obtained a reputation as an 

 odontalgic (Gerbi, Latreille). Some species of Carabidce, Chrysomelid&, and 

 Cochinellidai have been mentioned as possessing similar properties (Caradori, 

 Hirsch). 



