. TIHYAC0PHIL1D.E. AGAPETUS. 155 



ciliated on the hinder and inner margins ; anterior with more or less furcate 

 longitudinal nervures, but very rarely with transverse ones^ or with a dis- 

 coidal areolet ; posterior rather shorter and smaller, slightly folded on the 

 inner edge : abdomen moderate, of the males occasionally furnished with 

 hairy appendages beneath, and in both sexes sometimes also at the apex: 

 legs long and slender, tibice more or less armed with spurs. 

 Larva with or without external respiratory organs, not residing in a case ; 

 pupae inclosed in a double envelope, the inner one scaly, the outer silken and 

 mixed with small stones and other foreign materials : they reside in rurming 

 waters. 



The insects of this family are for the most part of small size, and 

 are extremely difficult to discriminate from each other without careful 

 attention to their structure, owing to the similarity of their colouring, 

 and their paucity of markings : it is much to be regretted that 

 M. Pictet, in his otherwise valuable work on these insects, has 

 almost totally omitted to notice the peculiarities of neuration of the 

 wings, or the numbers and positions of the spurs on the tibiae of the 

 respective species, especially of this family, which he seems to have 

 mixed together most heterogeneously : they may generally be distin- 

 guished by having the two basal joints of the maxillary palpi very 

 short, and the terminal one not longer than the preceding, and 

 ovate. 



The species may be thus divided into genera : 



Tibiis anticis 2-calcaTatis : 



J/js omnibTiS areo/a discoidali : .... 8. Glossosoma. 



anticis solum areola discoidali : . . .9. Tinodes. 



omnibus areola discoidali nulla ; 



Antennis art", basali maximo : . . .6. BeRjS:a. 



parvo ; 



^/is elongatis, angustis, obtusis : . • 7- Anticyka. 



brevibus, rotundatis : . . .5. Agapetus. 



Tibiis anticis 3.calcaratis : . . . . .10. Rhyacophila. 



Genus V.— AGAPETUS, Curtis. 



Antennae shorter than the wings, and not longer than the body, stout, especially 

 at the base, and divaricating: palpi rather short, slightly pilose: head 

 densely clothed with woolly hairs above : eyes globose, rather prominent : 

 wings short, with dense elongate cilia on the hinder and inner margins, 

 anterior rounded at the apex, with four single longitudinal nertures on the 

 costal portion of the apex, and with three bifid ones on the anal portion : 

 abdomen short, robust ; of the male furnished with an incurved spine in the 



