218 



A closer study of the Indian species of Psyclioda and Pericoma 

 has resulted in several characters being found which were not 

 made use of in my first paper on this family. 



Firstly, there is the presence or absence of distinct scales on 

 the wings nearly always of some shade of brown, although 

 sometimes appearing whitish or greyish when viewed from certain 

 directions. These scales appear in only one species (apicalis*) of 

 Psyclioda, whilst in Parabrunettia they are present in some species 

 on both the upper and lower surfaces of the wing, and in others 

 on the lower surface only. In referring to these scales, allusion 

 is not made to a certain number of scale-like hairs or even true 

 scales, few in number and irregularly placed, at the base of the 

 wing, and which may be present in many species, possibly adven- 

 titiously ; but only to cases where the scales are numerous, 

 eminently conspicuous and arranged in regular rows, covering 

 thickly the whole of such portion of the wing-surface as they 

 may occupy. 



The second character, which, like that of the scales, is quite 

 consistent m its occurrence or absence, is that of the hairs, com- 

 paratively soft or at least less bristly than usual, closely covering the 

 membrane of the wing as well as the veins and arranged longitudi- 

 nally or nearly so, so that they do not form the "criss-cross" 

 pattern as in the case of all those species in which the hairs are 

 confined to the veins. It is quite obvious at a glance to which 

 category any wing belongs except in the densely scaled ones. 



The third consistent character is the position at which the 

 2nd longitudinal vein forks (always near the base of the wing) ; 

 whether before or after the origin of the 3rd longitudinal vein. 



Further characters appear less definite and should best be 

 applied only to the separation of closely- allied species, being 

 liable to occasional variation. The three principal characters 

 above specified can be used in both Psychoda and Pericoma* 



Genus PSYCHODA, Latr. 



Psychuda, Latreille, Precis gen. Ins. p. 152 (1796). 

 Phalcenula, Meigen, Nouv. class. Mouches (1800). 

 Trichoptera, Meigen, Illig. Mag. ii, p. 261 (1803). 

 Tinearia, Schellenberg, Gen. des Mouches (1803). 



GENOTYPE, Tipula phalcenoides, L. 



Head small, rounded, much arched, much developed posteriorly, 

 narrower than the thorax and placed very low down on the latter. 

 Frons equally broad in both sexes ; eyes kidney-shaped. Ocelli 

 absent. Proboscis short. Palpi 4-jointed, moderately long and 

 prominent, the joints not greatly differing from one another in 

 length. Antennae moderately prominent, somewhat long, 15- or 



* Probably they will be found to apply equally well to at least Para- 

 brunettia also, when this genus is more closely characterised and its species 

 better understood. 



