THE GENERA OF BRITISH MOTHS. 109 
PLATE XLII. 
No. 1.—The Horse Chestnut (Pachycnemia Hippocustanarie). | No, 8.—The Tissue (Triphosa dubitata). 
No. 2.—The Streak (Eucestia Spartiata). | No. 84.—The Scarce Tissue (7. certata). 
No. 3.—The Caterpillar of the Streak. No. 9.—The Yellow Shell (Camptogramma bilineata). 
No. 4.—The Small Waved Umber (Phibalapteryx Vitalbata). | No, 10.—The Scallop Shell (Calocalpe undulata). 
No. 5.—The Narrow-barred Carpet (Plemyria gemmata). No. 11.—The Black-veined (Siona dealbata). 
No. 6,—The Dark Umber (Philereme Rhamnata). | No. 12.—The Snowy (G@ypsochroa nivecta). 
No. 7.—The Broom Scallop (Schidax Sparsaria). 
Tue fifteenth sub-family of the Geometride is that of the Chesiadi, containing the nine genera 
illustrated in the present Plate. 
The genus Pachycnemia. The insects assigned to this genus have the antenne slightly thickened 
and serrated in the males, and simple in the females. The palpi project, in the form of a short straight beak. 
The abdomen is slender and rather long. The larva is not well known. There is but one British species. 
Pachycnemia Hippocastanaria (the Horse Chestnut, No. 1). This inconspicuous insect appears throughout 
the summer, there being probably several broods from March to September. It is found in heathy districts, 
especially the open places in the New Forest, about July. The larva has not been accurately described. 
The genus Lucestia (the Chesias of Treitschke). In this genus the antenna are simple in both sexes. 
The palpi are long, scaly and close together, like a beak. The abdomen is long and rather stout; the wings 
are long, narrow, glossy, and rather lanceolate in form; and when at rest, they descend each way from 
the ridge over the back like a roof. The Caterpillars are slender and smooth. The Chrysalides have the 
yentral protuberance rather prominent. There are two British species. 
Eucestia Spartiata (the Streak). This remarkably distinct species receives its popular name from 
the white streak which extends from the points of the front wings to near the base. The Caterpillar 
(No. 2) feeds on the common Broom, and the perfect inseet appears in October, in places where that 
plant is abundant. 
The other species is £. obliquata (the Chevron) which has the same lancet-formed wings, but is easily 
distinguished by the absence of the white streak, and the more regular transverse bands, especially the 
broad dark one beyond the centre, near the external edge. 
The genus Phibalapteryxz. The insects assigned to this genus have the antenne simple in both 
sexes. The body has generally a double row of black spots, and sometimes a black line. The front 
wings have the tip somewhat prolonged and in some species rather hooked. The Caterpillars are very 
long and slender and rather attenuated towards the head. The Chrysalis is formed in the earth. There 
are four British species. 
Phibalapteryx Vitalbata (the Small Waved Umber, No. 4). This clearly marked species, with its 
transverse wave of rich umber running from the anterior tip of the front wing to the inner side of the 
base, is by no means a common insect. The Caterpillar is described by M. Guénée as reddish gray 
marbled with black, with black lines on the back, and a flesh-coloured line at the sides. It feeds on the 
