The Mouth-par U of the Nemocera, etc. By W. Wesche. 37 



Brachycera, the Bombylidre and the Syrphida?. In the latter family 

 is less variation in the mouth-parts than in any other large family 

 in Diptera ; Rhingia campestris Mg. has, however, a very long 

 labium, geniculated in a curious manner. 



Group 3. — The minute Cecidornyidre appear to be without 

 trachete on the labium, the hypopharynx is ciliated, the labrum well 

 marked, and the palpi are four-jointed (pi. V. fig. 8). 



The large family of the Chironomidre has fairly constant cha- 

 racters, though Ceratopogon appears to be specialised. The tracheal 

 of the paraglossaj are but slightly developed, the palpi are attached 

 to the stipites, and the cardines are long, though all the other parts 

 of the maxillse are wanting ; the hypopharynx is ciliated for some 

 distance down its sides ; the labrum is less modified than in most 

 families, being little more than a fold of skin. The palpi are four- 

 jointed, though they appear to have only three joints — a careful 

 examination shows the lowest joint to be very short, and under- 

 neath is the palpifer, which adheres to the stipes (pi. V. fig. 10). 

 These insects are said not to take food in the imaginal stage. 



Owing to the imperfection of some of my preparations, I was 

 inclined to consider the palpi in this family as labial, regarding 

 them as homologous with those found in the Bibionida). Mr. 

 A. H. Hammond, F.L.S., pointed out to me that in his, and Prof. 

 L. C. Miall's paper,* they had traced the palpi of C. dorsalis Mg., 



* ' The Development of the Head of the Imago of C'hironomus,' Trans. Linn. Soc. 

 London, Zool., ser. 2, v., 271-2. 



EXPLANATION OF PLATE VI. 



1. Trophi of Stratiomys chamasleon L. Dorsal view. 



2. Paraglossae of Bibio hortulanus L. Dorsal view, but part of the mernbrano has boeu 



removed to show the fused mandibles on the ventral side. 



3. Labrum of B. hortulanus. 



4. Hypopharynx of B. hortulanus. 



5. Labial palpus of B. hortulanus. 



0. Trophi of Dilophus febrilis L. Dorsal view, showing the position of the labial 

 palpi. 



7. Paraglossae of D. febrilis, ventral view, showing the small remains of the mandibles 



on the ventral side of the labium, corresponding with those on the labium of 

 B. hortulanus. 



8. Trophi of Conops quadrifaseiata Deg. Lateral view, showing the very rudi- 



mentary state of the maxillary palpi, while the labial are aborted. 



9. Labrum of Jlolichopus griseipennis Stan. Lateral view. 



10. Hypopharynx of J), griseipennis. Lateral view. 



11. Labium and paraglossre of D. griseipennis. Ventral view, showing the fused 



mandibles and the cardines of the maxillae on the dorsal side. 



12. Labium and paraglossae of I), griseipennis. Dorsal view. 



13. One of the tracheae of D. griseipennis, further enlarged. 



14. Labial palpus of D. griseipennis. 



15. Trophi of Lonchoptera flavicauda Mg. Lateral view. 



16. „ of Pipunculus zonatus Ztt. Lateral view. 



