204 MANDIBULATA. TRICHOPTEKA. 



than the two preceding united; labial 3-articulate, the last joint ovoid : 

 wings furnished with a series of transverse nervures, forming a tlexuous or 

 repanded line towards the bifurcations of the longitudinal ones ; posterior 

 wings ample, considerably folded within: abdomen moderate, slightly- 

 compressed : legs rather short : tibia mostly furnished with a pair of long 

 spurs at the apex, and the two hinder pair with others about the middle; 

 the tibiae themselves and the tarsi very frequently armed with short spurs 

 beneath. Larva residing in a moveable case of various forms, and differently 

 composed : the head and thorax are scaly, and the legs short : the respira- 

 tory organs are isolated, and arise transversely on the upper and under 

 surface of the body. 



The insects embraced in this family are amongst the largest of the 

 order, especially those of the typical genus, some of which are very 

 bulky: in the structure of the oral organs there is considerable 

 difference, in general, between the sexes, the maxillary palpi of the 

 males being mostly 3- or 4-jointed, while those of the females are 

 invariably 5-jointed ; the antennas are longer than the body, but 

 shorter than the wings, and are rather stoutish : the wings are 

 distinctly furnished with a somewhat repanded series of transverse 

 nervures, placed a little beyond the middle, and the posterior pair 

 are much folded ; in the anterior there is considerable diversity of 

 outline, as well as of neuration, whence the species may be readily 

 subdivided in groups^ or genera : the tibiae and tarsi are mostly 

 armed with short rigid spire-hke setae, and the legs are rather short. 

 The larvae reside in moveable cases, composed of various substances, 

 and of various forms ; the head and thorax are scaly, and the rest of 

 the body soft, the first abdominal segment being, in general, much 

 dilated and rounded on the sides ; the terminal joint is truncate, and 

 furnished with two hooks. 



The British species may be thus divided into genera : — 



TliJiis^ baud setigeris : . . . . .35. Neuronia. 



setis armatis ; 

 Corpus latum, depressum : . . . . .34. Agrypnia. 



subcompressum, baud depressum ; 

 ^fts setis erectis ornatis : .... 31. CHyETOPTER\K. 



pilosis, vix setigeris; 

 Palpi maxillares 



arti°. ult". breve, subelliptico : . . .29. Phryganea. 



elongate, filiformi 

 Alls anticis latis, versus apicem dilatatis, margine postico 



rotundato: . . .30. Halesus. 



/ angustis, margine postico rotundato : , . 33. Anabolia.. 



oblique truncate . . 32. Limnefuilus, 



