44 Transactions of the Society. 



Group 6. — The Phycodromidae have paraglossae much of the 

 same type as the Ortalidae, and, like them, totally devoid of teeth. 

 The labial palpi are stiffly haired, and have a long hair on the tip. 

 The maxillae end in a leaf-shaped scale, covered with a fine 

 pubescence. I have mostly taken these insects on sea-weed, and 

 they probably feed on the juices of those plants (pi. VII. fig. 6). 



The mouth-parts of the Heliomyzidae have but little to dis- 

 tinguish them from those of the Phycodromidae ; the likeness in 

 the paraglossae is very marked, the ends of the maxillae are some- 

 times identical in shape, but have a finer pubescence. The labial 

 palpi in those examples I have examined have no long hair on the 

 lip. I have usually found these insects on damp herbage, and 

 there they probably find their food (pi. VII. fig. 7). 



The Sciomyzidae have a great affinity with the Heliomyzidae, 

 and we may perhaps consider the ciliated costal vein which dis- 

 tinguishes the latter family as almost a generic character, though 

 it is undoubtedly a useful one. The tracheae are as numerous as 

 in the two preceding families ; the maxillae are of the same shape, 

 with perhaps a trifle less pubescence ; and the palpi are haired, 

 and with a long hair on the tip as in the Phycodromidae (pi. VII. 

 figs. 8, 9). 



The Sapromyzidae have the same type of maxilla?. There 

 are no teeth on the paraglossae, but the rings of the tracheae are 

 strong and thick, and the part is very different from that found 

 in the three preceding families (pi. VII. figs. 10-12). 



Group 7 is wholly confined to the acalyptrate Muscidae. The 

 character which distinguishes it from the previous group is the 

 presence of four palpi. Sometimes the laciniae may be thought 

 to be present, but even then it is so thickly haired as to make 

 certainty as to its real nature impossible. 



The Opomyzidae have tracheae like the Phycodromidae. The 

 maxillae in Balioptera are characteristic, the cardines rather 

 rounded, and tapering to the part that is ordinarily the lacinia, but 

 here is thickly haired and distinctly like a palpus. 0. gcrmina- 

 tioncs L. differs, in having the maxillae of the same type as the 

 Phycodromidae. These insects can be taken anywhere and every- 

 where in long grass (pi. VIII. fig. 5). 



I have already referred to the peculiar mouth-parts of Sepsis 

 cynipsca L., in my remarks on Group 3. Ncmopoda cylindrica F. 

 explains the homologies, as it possesses well-developed labial 

 palpi, and distinct maxillary palpi in the usual position on the 

 cardines. The tracheae are less marked than in Sapromyza. SaUella, 

 scutettaris Fin. is very much the same type as Nemopoda (pi. VIII. 

 fig. 6). 



In the Ephydridae the mouth is relatively much developed. 

 There is great variability in the character of the tracheae, such sur- 



