416 EXTERNAL ANATOMY OF INSECTS. 



the last place to be considered. I shall begin with the 

 Mouth, or rather the orifice in which the trophi or organs 

 of manducation are inserted. In some insects, as was be- 

 fore observed, they occupy all the under-side of the head, 

 as in the Arachnida, Myriapoda, &c; but in the great 

 majority they fill an orifice in its anterior part, which in 

 some instances, as in Lampyris, the Lepidoptera, Ci- 

 mex L., Truxalis, appears to be nearly under the head ; 

 but in general it terminates that part, though it extends 

 further below than above. In Chermcs, a Homopterous 

 genus, the promuscis is stated to be in the Antepectus, and 

 consequently the mouth ; but, as I shall endeavour to prove 

 to you hereafter, this is a fallacy. In the males of the 

 species of Coccus there is no mouth at all. In that of the 

 elm (C. Ulmi) in lieu there are ten little shining points, 

 arranged two before and two behind in a line, and three 

 on each side in a triangle 1 . It is to be observed that the 

 orifice of which I am speaking is usually much smaller 

 in those insects which take their food by suction, the 

 Hemiptcra, Lepidoptera, Diptera, &c, than in the mas- 

 ticating tribes. With regard to the real mouth, or that 

 through which the food enters, I have nothing at present 

 to observe, except that it lies between the upper-lip and 

 tongue, is sometimes covered by a valve, as in Apis, 

 Vespa b , &c, and is different in the masticators and 

 suckers. 



I shall next offer a few observations seriatim, as they 

 stand in the Table, upon the organs of manducation ; 

 which, to avoid circumlocution, instead of Instruvienta 



a Reaum. iv. 40. Latreille Fourmis, 328--. h Plate VII. Fig. 2. k". 



