150 Mr. R. M‘Lachlan’s Monograph of the 
The only locality that I know to produce this species is the 
remnant of the Croydon Canal at Forest Hill, Kent, where it 
occurs in May and June. As this locality will probably be shortly 
destroyed, it is to be hoped that the species will be found else- 
where. 
It is allied to Philopotamus urbanus, Ramb., but appears to be 
distinct. Dr. Hagen, who possesses the type of uwrbanus, says 
that it differs from flavidus in that the anterior wings are almost 
entirely pale without darker markings, and has some slight dif- 
ferences in the comparative length of the forks. Moreover, it 
possesses evident fringes on the anterior wings, and rather long ones 
on the posterior. In C. flavidus the anterior wings have scarcely 
any evident fringes, and those on the posterior are very short. 
Plectrocnemia aurata of Kolenati is also apparently an allied spe- 
cies, yet the neuration, according to the figure, seems to possess 
fork 1 in the anterior wings, which, if correct, will preclude its 
being placed in Cyrnus. 
Genus Ecnomus, M‘Lachlan. 
Antenne much shorter than the wings, the basal joint scarcely 
longer or stronger than the others. Head hairy. Ocell!i absent. 
Maxillary palpi with two rather short and equal basal joints; two 
following scarcely longer and somewhat dilated; fifth as long as 
the others united. Mesothorax short and robust. Anterior 
wings long and very narrow, very slightly dilated before the 
elliptical apex ; hairy clothing short and dense ; a transverse vein 
unites the costa and subcosta near the middle; the radius and 
subcosta unite beyond the middle, but divide again before their 
termination; discoidal cell closed, short and broad; forks 1, 2, 3, 
4 and 5 present, No. 1 very short; four transverse veins towards 
the apex, and one towards the base. Posterior wings scarcely 
folded, very narrow at the base, but considerably dilated before 
the very obtuse apex; costal margin slightly elevated in the middle, 
somewhat excised towards the apex; anal portion not developed ; 
forks 2 and 5 only present; one transverse vein, uniting the ramus 
discoidalis and ramus thyrifer; no discoidal cell. Legs long ; 
intermediate tibiae very slightly dilated in the female; anterior 
tibiae with one very short median and two moderately long apical 
spurs; intermediate and posterior tibia each with two pairs of 
Jong and unequal spurs. Abdomen rather slender. In the male 
the only visible appendices are the inferior, which are largely 
developed ; between these on the ventral surface arise two long 
curved sheaths, 
