2 Mr. K. J. Morton on 



collectors can hardly attempt to discriminate between 

 them in the field. 



In using as the principal criterion for specific determin- 

 ations, the genital appendages, I have followed the best 

 traditions of systematic work amongst the Trichoptcra. 

 Experience proves that figures of these parts are indis- 

 pensably necessary if a reference to types is to be avoided. 

 With a fair preliminary knowledge of the subject and 

 moderate caution, such hgures, even when little more than 

 diagrams, can be used with the most satisfactory results. 

 It is to be regretted that many North American Trichcqytera 

 are being described witliout due regard to these parts, 

 although their authors say the final determination of 

 species must rest on sexual characters. They thus admit 

 that they have not attempted to make their descriptions 

 sufficient, an admission that does not require further 

 comment. 



Although tlie majority of the species now described 

 belong to groups which have no near exponents amongst 

 the European species, and although some of the species 

 will be set apart ultimately in other genera, little would 

 be gained in the meantime by splitting up the great 

 genus FJiyaco-pliila. Acting on the recommendation of Mr. 

 McLachlan 1 retain all in the genus Bhyacophihi, a course 

 which, at present, my oAvn views quite approve. I think 

 all the species now made known, will fall under the short 

 diagnosis given in the "Revision and Synopsis of European 

 Trichoptera," p. 434, although all will perhaps not be found 

 to agree in every particular with the details given on pp. 

 432-3 of the same work. I have accordingly placed in 

 the front of each description, some of the more important 

 characters which may be found useful in establishing 

 gruups or even genera hereafter. 



1. Bhyacoplvila lanceolata, n. sp. 



Ventral abdominal tooth obsolete or absent in both sexes. Ninth 

 segment in the ^ continued broadly ventrally. No median process ; 

 lateral lobes, very large, contiguous. 



Wings elongate, apex sub-falcate ; radius furcate at apex ; apical 

 fork No. 1 extending inwardly further than No. 2. Costal hairs 

 simple. 



Fore wings greyish-yellow or stramineous ; anterior part pale, 

 with a few elongate spots on the nervures ; costal area faintly 

 irrorated ; a strongly-maiked brown dot on the costal margin just 



