HYLOTOMA TJSTULATA. 57 



Bluish -greenish or bronzy- black ; knees, tibiae, and tarsi yellowish- 

 white, apex of posterior tibiae and tarsi testaceous or fuscous ; antennae 

 black. Wings yellowish, especially at base ; costa and stigma yellowish - 

 testaceous ; base of stigma and a cloud below it, which extends to the 

 cubital nervure, fuscous or fuscous-black. Nervures testaceous at base, 

 darker at apex ; third cubital cellule a little shorter than the second, of 

 nearly equal length on both sides ; third transverse cubital nervure 

 curved ; the second recurrent nervure is received not far from the second 

 transverse cubital nervure and is occasionally joined to it. Usually 

 the third cubital cellule is clearly shorter than the second, but in some 

 specimens it may be a little longer. The third joint of maxillary palpus 

 is not much longer and thicker than the fourth. The sixth is only a 

 little longer than the fifth. 



Length 4 5^ lines. 



Ab. a. ? wings not yellowish, but clear hyaline. 



b. $ wings not yellowish, nervures,costa, and stigma 

 black or fuscous-black ; tarsi and apex of tibise broadly 

 black. 



c. ? and cT apex of tibiae and tarsi black. 



d. 3 fascia below stigma almost obsolete, legs 

 black, tibise white at base. Body bronzy black ; 

 = ? expansa. 



e. Second transverse cubital nervure interstitial. 



/. Hind wings with transverse cubital nervure obso- 

 lete (in Ab. b). 



No author describes ustulata as a variable insect, 

 yet in Scotland it seems to vary considerably, especi- 

 ally in the coloration of the legs and wings. Thus 

 Thomson separates it from H. fuscipes and ciliaris by 

 the wings being yellowish and the tibia? and tarsi pale 

 yellow, while he characterises the two species I have 

 named by the terms " alse hyalinae ;" but neither the 

 colour of the legs nor of the wings can be relied upon 

 as marks of distinction between ustulata and fuscipes. 

 With the darker specimens of ustulata the best marks 

 of distinction are that fuscipes has the third cubital 

 cellule a little longer than the second, while in ustulata 

 it is shorter, and in fuscipes the sixth joint of the 

 maxillary palpus is double the length of the fourth ; in 

 ustulata not more than one and a half times the length, 

 In ustulata, too, all the tibiae are white (often broadly) 

 at the base. 



