294 W. WESCHE ON THE PROBOSCIS OF THE BLOW-FLY. 



Fig. 12. Labium of //. pertinens ?, lateral view; the hypo- 

 pharynx, labrum, maxillae, maxillary palpi, and 

 mandibles have been removed. To show the absence 

 of any plate on the upper surface and of any median 

 or lateral structure on the mentum. The situation and 

 character of the tracheae have been indicated. 



Fig. 13. Maxilla, maxillary palpus, stipes, and cardo of H. per- 

 tinens ? . To show the connection of the palpus 

 with the stipes and for comparison with Figs. 3 and 4. 

 I. lacinia (maxilla) ; nip. max. palpus ; pf. palpifer ; 

 s. stipes ; c. cardo. 



Plate 23. 



Fig. 1. Proboscis of Siphona geniculates, Deg. The parts have 

 been modified to enable the insect to probe the cavities 

 of flowers ; the smaller circle shows the paraglossae 

 with the modified tracheae ; the teeth, found on the 

 corresponding part in the Blow-fly, have completely 

 disappeared. 



Fig. 2. Proboscis of Stomoxys calcitrans, L. The parts have been 

 modified for blood-sucking. The smaller circle shows 

 some of the teeth found on the paraglossae. The 

 following letters are used on this plate : Ip. labial 

 palpus ; pg. palpiger ; pr. paraglossa ; mn. mentum ; 

 sm. submentum ; Ir. labrum ; h. hypopharynx ; s. 

 stipes of the maxilla ; c. cardo of the maxilla. 



Journ. Quek-ett Microscopical Club, Ser. 2, Vol. X., No. 63, November 1008. 



