46 1< EXTERNAL ANATOMY OF INSECTS. 



receives an increment at the expense of others, and the 

 whole oral machine is fitted for suction ; or where some 

 parts appear to be deficient, so that this may be called 

 an imperfect mouth. At first sight one would regard the 

 trophi of a bee as of this description ; but this is not the 

 case, since it has all the ordinary organs, though the 

 tongue is unusually long, and looks as if it was made for 

 suction ; which, however, as you have been informed, is 

 not the case. 



There are Jive kinds of imperfect mouth to be met 

 with in insects that take their food by suction, each of 

 which I shall distinguish by a separate denomination. 

 The first is that of the Hemiptera Order : — this I term 

 the Promuscis; the second is that of the Diptera, which 

 with Linne I call Proboscis ; the third, peculiar to the 

 Lepidoptera, is with me an Antlici; the fourth, which I 

 name Rostrulum, is confined to the Aphaniptera order, 

 or genus Pulex L. ; and the last is Rostellum, which I 

 employ to denote the suctory organs of the louse tribe 

 (Pediculidte). 



1. Promuscis a . — The organ we are first to consider 

 has usually been denominated Rostrum : but since that 

 term is likewise in general use for the snout of insects of 

 the weevil tribes [Curculio L.), I think you will concur 

 with me in adopting the one here proposed, for the very 

 different oral instruments of the Hemiptera. Illiger has 

 employed promuscis to denote those ofbees b : but since, as 

 I have just observed, they consist of all the ordinary or- 

 gans, they seem to require no separate denomination : 



a Plate VI. Fig. 7-9. a', b', c', d'. b Magr/z. 1806. 



