and oil the nature of the background opposed to the specimen. This, 

 in the first case, is because some of the wing-markings are due to 

 bristling hair, brushed up as it were, on the nervures in particular 

 regions, while others are produced by prostrate or appressed hairs. 

 The bristling hair resembles that of Rydroptilidce, a I'amily of the 

 TricJioptera, excepting that the individual hairs in PsycJiodidce appear 

 to be smooth, and not serrulate or roughened microscopically like 

 those hairs in that other Family. In another respect — scales on some 

 o£ the wing nervures — the J* Ulomyia, and a few species of Pericoma, 

 present analogy with certain representatives of the Sericostomatidce, 

 another Family of the Trichoptera. 



In preparing the Analytical Key to Groups, Grenera, &c., and in 

 the tabulation of species of Sections of Grenera, characters apparently 

 conducive to natural assemblage of species have been selected ; but 

 Group II had to be scheduled without reference to Phlebotomus, this 

 genus being unrepresented in the collections to which access was ob- 

 tained. In view of the author's intention of travelling abroad before 

 the manuscript and figures could be completed, the distinctive points 

 of many of the species have been described in the tabulations more 

 in detail than might have been deemed desirable under other circum- 

 stances, with the object of securing, as far as possible, the main results 

 of the investigation, in case anything might put a stop to the work. 

 The supplementary matter is in an advanced stage of preparation. 

 The tables have been revised and adjusted to the requirements of 

 practical work up to the end of September, 1892. It is unfortunate 

 that some of the leading clues are of a nature that demand the 

 exercise of very close scrutiny on the part of the investigator ; but 

 tested repeatedly, they have hitherto always yielded accurate deter- 

 minations of species— supplying a desideratum. 



The most noteworthy points in wings are the inward destinations 

 of the radial and postical nervures. Next in importance maj'' be 

 reckoned the position of the extremity of the wing, relative to the 

 terminations of the cubital and prsebrachial nervures, and the form 

 of the wing's apex ; and then may be ranked the positions of the 

 points of bifurcation of the radial and pobrachial nervures in relation 

 to the wing as a whole, or to the ends of certain of the other 

 nervures, or to one another. In certain species it is hardly possible 

 to ascertain exactly where the radial ai;d postical nervures terminate 

 towards the base of the wing, without removing the hair thereabouts, 

 a line of hairs being liable to be mistaktai for part of the radius, and 

 making it appear to terminate in the subcostu, or else in the basal 



