MAXILLAEY PALPI IN DIPTERA< 229 



Note. — The Homology of the Car dines. 



It has been objected that the homology of the levers of the labi'um in the Muscida? 

 (the " apodemes " of Dr. Benjamin Lowne) with the cardines of the maxillae is not quite 

 clear. As this is of vital importance to my theory, I have enlarged my argument and 

 summarized it as follows : — 



1. In Ves-pa and Apis the cardines are on the same plan as in Mmca. They are 



generally admitted to be the "hinges" of the "posts" supporting the palpifers 

 and other parts. If these are cardines here, so must they be in Diptera. 



2. It may be urged that the fact that the levers are enclosed is against the theory 



that they are cardines. This objection has no weight. The cardines being the 

 lowest part, they would (if there were any tendency in that direction) be the 

 first part to be embedded. 



3. In Culex, $ , the levers are undoubtedly cardines, the four-jointed palpi are affixed 



to them, and though the palpifer is differentiated, I have failed to see the point 

 where the stipes and cardines fuse. 



4. In Eristalis and Helopldlus parts of the maxillae are present with palpi. It is 



impossible to deny the homology of the posterior ends with the apodemes. 

 Therefore as these parts bear the palpi, they must be in some part the stipites ; 

 and as similar parts in Vespa and Apis are admitted to be the cardines, in 

 Eristalis and HelopMlus they must be the fusion of the stipites and cardines, 

 which applies equally to the Muscidae. , 



5. It may be suggested that in the Muscidae the levers are so obviously necessary to 



work the labrum and hypopharynx that they would specially evolve. To this it 

 may be answered that the levers are jsresent in Culex. In the female they liinge 

 on to the blades of the maxillae ; in the male they work the long palpi cliarac- 

 teristic of that sex. So in Diptera we know of three uses of the cardines, showing 

 there exists a tendency to utilize this part. 



6. In the small Ephydra figured (which, judging from a determination of Mr. Piffard, 



is Hydrellia griseola, Fallen), in the same places as the apodemes are also found 

 complicated organs, which are evidently the complete maxillie. 



7. The negative proof — if they are not cardines, what are they ? 



EXPLANATION OF THE PLATES. 



The lettering applies to all the figures, 

 a, labium. k, stipes. 



b, paraglossa. 



c, ligiila. 



d, labial palpus. 



e, palpiger. 

 /, mandible. 

 g, maxilla. 

 h, galea. 



i, lacinia. 



Ill, cardo. 



n, maxillary palpus. 



o, palpifer. 



p, mentum. 



r, subraentum. 



*, labrum. 



/, hypopharyu.v or lingua. 



