1S95.1 209 



universally the satne, and the extent of the bristling hair on identical 

 nervures varies in different minor groups of species ; and, therefore 

 when its limits and position are correctly ascertained, it yields data 

 worth taking into account. Where the hair is bristling, the hairs tend 

 to be secund and in some measure reclinate inwards ; elsewhere they 

 are either distichous or tristichous and slant outwards, two ranks in 

 the latter case spreading pinnately over the membrane, and the third 

 rank ascending obliquely. The ruffled hair in Si/corax is exceptional 

 in texture, being serrulate, as in IlydroptiUdcc. 



Some additions may now be made of introductory matters un- 

 mentioned in the Synopsis. Ilalteres of Psi/chodi(l(B are usually clad 

 with appressed scales, seldom with hairs. Sexual differences in the 

 dimensions of corresponding parts of homologous legs are as a rule 

 too small to be detected without careful admeasurement, and are rarely 

 worth recording. Many Psi/chodid(S possess appendages to the antennae 

 homologous with the chitinous bristles of joints in the flagellum noted 

 in the Synopsis under Pericoma soleata, ante, 2nd ser., vol. iv, p. 126. 

 Their nature is undetermined. In some species there is danger of 

 ill-focussed hairs being mistaken for them ; but they are not always 

 hair-like nor setifortn. In Pericoma incerta they have the appearance 

 of longitudinally striate squamulre ; and in species of the 5th Section 

 of that genus their form is digitate. 



Recipients of named Psychodidce distributed from the author's 

 collection in September, lS9i, are requested to note that under JSTo. 31, 

 Pericoma fusca, two species were intermixed, viz., P. auricidata, Curt, 

 (the one described and illustrated in the Synopsis), and P. fusca, 

 Macquart — vide post, Pericomor, 5th Section, species Nos. 81 and 32. 

 There are, therefore, 41 described British species of this Family 

 instead of 40. 



Note to Analytical Key ; ante, 2nd ser., vol. iv, p. 31. — The two 

 Groups of genera roughly scheduled in the Syno|)sis may well rank 

 as Sub- Families, and be characterized more methodically, as hereunder, 

 for general use. The first comprises all the forms classed under 

 TJlomyia, Pericoma, and Psychoda ; the second, two British genera, 

 Sycorax and Trichomyia, besides one foreign genus. Phlebotomies. The 

 number of joints in the palpi is no longer taken to be a distinctive 

 characteristic of the main divisions of the Family ; it appears to be 

 four throughout the Psychodidce. Schiner considered these organs to 

 be 5-jointed in TTJomyia and Pericoma — probably mis-reckoning the 

 number in dried specimens ; and in the vSynopsis they were wrongly 

 stated to be 3-jointed in Trichomyia and Sycorax — the basal joint 



