SYNOFSIS OF THE BRITISH PHRYGANID^. 57 



the appendices anales, which are here of especial importance, 

 cannot be clearly explained without figures, or long detailed 

 descriptions ; and I have, consequently, for the most part, 

 left them unnoticed in the " Synopsis," although they have 

 always been carefully examined by me, and indeed the 

 reduction of Stephens's species depends upon their examina- 

 tion. 



With regard to the determination of the Phryganidce I 

 have to offer the following hints : — 



I. In the first place the palpi, and especially the maxillary 

 palpi, are to be carefully examined, and the number of their 

 joints determined. If there be less than five (always in 

 males) the insect belongs to the Heteropalpi. It is cer- 

 tainly an unfortunate circumstance that the females of these 

 always bear five joints, but by taking into consideration the 

 other characters, and by the help of a little practice, there 

 will rarely be any doubt. The Hydropxychidce, which are 

 otherwise so difficult to separate, are readily distinguished 

 from all others by the abnormal form of the last joint of the 

 palpi. This is very long, and composed of numerous small 

 joints closely pressed together ; this is not to be confounded 

 with the forms in which there is a flexibility [of the last 

 joint] without any division into joints (e. g. Leptocerus). 

 The relative proportions of the joints of the palpi form very 

 important and easily seized generic characters, especially in 

 the Isopalpi. 



II. Next to the palpi the antennae must be compared. 

 Their characters are usually distinctly perceptible, and con- 

 sist in the length and thickness of the antennae, and in the 

 proportions of the basal joint. At the same time it must not 



