36 EXTERNAL ANATOMY OF INSECTS. 



have no doubt that this is the true tongue. In Diptera it is 

 elongate and sharp-pointed, and is the part so named in Curtis's 

 figures o{ Anopheles and Tabanus. In Hymenoptera it is shorter, 

 but still evident, particularly in the bees, as Eucera, &c. In 

 Coleoplera, it is still less prominent, and assimilates to its 

 Lepidopterous form already described. In Orthoptera it 

 increases in size, and in the common cock-roach very nearly 

 approaches the shape, appearance, and relative size of the human 

 tongue. In Locusla it is very large. In Hemiptera the 

 tongue is the central and generally the shortest organ of the 

 mouth : it has not, however, escaped the lynx-eyed researches 

 of Savigny and Leon-Dufour. 



The next letter relates to the segments which bear the organs 

 of locomotion. 



I am, &c. 



Edward Newman. 



Deptford, March 1, 1833. 



