THE society's NOTE-BOOKS. 265 



expressed in Mr. Lowne's own words, where he says (at bottom of 

 p. 45*) that they "form joints with their apodemes," and this 

 joint will, I think, be found on examination to mark too great a 

 separation between the parts to allow much force to an argument 

 drawn from their supposed continuity. Although, therefore, I am 

 disposed to doubt whether the lateral portions of the operculum 

 represent any portion of the maxillae, yet it must be thought that 

 in the Blow-Fly these organs are to be sought for in that portion 

 of the integument from which the palpi arise, namely, in the 

 scales and septiferous bands. 



It may be presumed that the differences of organisation in 

 the mouths of these two insects have reference principally to their 

 respective habits of feeding. The broad, expanded lobes of the 

 Blow-Fly, shown in Fig. 2, are doubtless well adapted for sucking 

 up the variety of fluid substances upon which the insect feeds. 

 The proboscis of the Syrphidas are much longer, and therefore 

 better suited to their flower-haunting habits ; the lobes too are 

 more compressed. 



The basal joint of the proboscis, called by Mr. Lowne the 



fulcrum, is similar in principle in both insects, but somewhat 



different in shape, as may be seen by comparing the part marked 



f. in Figs. 9 and 10. The position of the fulcrum within the head 



is shown in Fig. 6. 



Another important difference between the mouths of these 

 two insects is the absence in the Drone-Fly of the forked 

 character in the rings of the false trachea, as seen in Fig. 8, which 

 represents a portion of one of these channels in the Blow-Fly, 

 flattened out. This seems to point to a less perfect development 

 in the former insects, as compared with the latter, which is further 

 confirmed by the absence also in the former of the chitinous 

 teeth, and their intermediate pillars referred to by Mr. Lowne in 

 his work, and shown in my Figure 14. I believe that both the 

 teeth and the pillars are modifications of forked rings. 



A. Hammond. 



EXPLANATION OF PLATES XVIII., XIX., XX., 



XXL. XXIL, XXIII. 



Plate XVIII. 

 Fig. 1. — Represents the specimen of Sphctria of the natural size, the 

 outline of the leaf being simply diagrammatic to indicate that 

 the piece shown formed only part of the leaf. 



Anatomy and Physiology of the Blow-Fly." 



* a 



