VI EXTERNAL STRUCTURE 3 I I 



The exact mode in which the proboscis acts is in several 

 respects still obscure, the views of Burmeister and Newport being 

 in some points erroneous. Towards the tip of the proboscis 

 there are some minute biit complex structures considered by 

 Fritz Miiller to be sense-organs, and by Breitenbach to be 

 mechanical instruments for irritating or lacerating the delicate 

 tissues of blossoms. It is probable that Miiller's view will prove 

 to be correct. Nevertheless the proboscis has considerable 

 power of penetration ; there being a moth, " Ophideres fuUonica," 

 that causes considerable damage to crops of oranges by inserting 

 its trunk through the peel so as to suck the juices.^ The canal 

 formed by each maxilla opens into a cavity inside the front part 

 of the head. This cavity, according to Burgess," is a sort of sac 

 connected with five muscles, and by the aid of this apparatus the 

 act of suction is performed : the diverticulum of the alimentary 

 canal, usually called a sucking-stomach, not really possessing the 

 function formerly attributed to it. 



The Pkothorax is very small, being reduced to a collar, be- 

 tween the head and the alitrunk, of just sufficient size to bear the 

 front pair of legs. Its most remarkable feature is a pair of pro- 

 cesses, frequently existing on the upper surface, called " patagia." 

 These in many cases (especially in Noctuidae) are lobes capable 

 of considerable movement, being attached only by a narrow base. 

 In Hepialus, on the contrary, they are not free, but are merely 

 indicated by curved marks on the dorsum. The patagia are 

 styled by many writers " tegulae." They are of some interest in 

 connection with the question of wing -like appendages on the 

 prothorax of Palaeozoic insects, and they have been considered 

 by some writers ^ to be the equivalents of true wings. The 

 Mesothoeax is very large, especially its upper face, the notum, 

 which is more or less convex, and in the higher forms attains a 

 great extension from before backwards. The notum consists in 

 greater part of a large anterior piece, the meso-scutum, and a 



^ Amer. Natural, xiv. 1880, p. 313. 



- For an account of the structures at the tii^ of tlie proboscis of this moth, and 

 of the beautiful manner in which the lobes of the maxillae are dovetailed together, 

 see Francis Darwin, Quart. J. Micr. Sci. xv. 1875, p. 385. For details as to 

 numerous proboscides, and as to the difficulties that exist in comprehending the 

 exact mode of action of the organ, refer to Breitenbach's papers, especially Jena. 

 Zeitschr. Naturw. xv. 1882, p. 151. 



^ See Cholodkovsky, Zool. Anz. ix. p. 615 ; Haase, i.e. p. 711 ; also Riley, 

 P. cnt. Soc. Wasiiiiujton, ii. 1892, p. 310. 



