INTRODUCTION 
The present catalogue of the Families Flatidae and Hypochthonellidae 
forms Part 13 of Fascicle IV of the General Catalogue of the Homoptera 
of the World which is devoted to the Superfamily Fulgoroidea. This was 
virtually complete at the time of the death of Dr. Z. P. Metcalf on January 
5, 1956. It was completed with the aid of Miss Virginia Wade, Research 
Analyst, who worked with Dr. Metcalf for the past seven years, and the 
technical advice of Drs. David A. Young, Jr. and Paul W. Oman of the 
Entomology Research Branch, Agricultural Research Service, United 
States Department of Agriculture. 
The catalogue of the remaining fulgoroid family (Issidae) and of the 
Cicadellidae is practically complete to the end of 1955, and we plan to 
publish these remaining portions under Dr. Metcalf’s authorship. 
Since the fulgoroid catalogues began to appear in print several changes 
have occurred in the classification of higher categories. One of the changes, 
the establishment of the Family Hypochthonellidae, can be covered more 
readily in this than in the remaining unpublished portion of the Ful- 
goroidea catalogue. 
The Family Hypochthonellidae, consisting of one genus with one species 
from the Ethiopian Region, was characterized as follows in the original 
description 1 : 
“Form cylindrical; derm weakly sclerotized, with sparse pubescence of 
microtrichia. Vertex, including occiput, moderately elongate, parallel-sided, 
shallowly convex, apically rounding into frons, frons longer than broad, 
lateral margins not or obsoletely carinate, clypeus elongate triangular, 
ecarinate; ocelli absent, compound eyes reduced, rostrum elongate with 
subapical j oint longer than apical. Pronotum long, anterior margin strongly 
convex, posterior margin concave, carinae weak or absent; mesonotum 
relatively large. Tegmina and wings present, reduced, not covering ab- 
domen. Legs of normal length and proportions, joints terete; post-tibiae 
laterally unarmed, with about five short spines apically; post-tarsi slender, 
basal and second joint only shallowly excavate distally, basal joint with 
about four spines distally, second joint unarmed; tarsal ungues of all legs 
relatively long and slender, arolia delicate, small, devoid of supporting 
slcerites. 
“Abdomen cylindrical, spiracles very small, a few wax-glands latero- 
distally on the sixth, seventh and eighth abdominal tergites. Aedeagus 
comprising a tubular phallobase and a tubular phallus with distal 
appendages. 
1 China and Fennah, 1952, Ann. Mag. Nat. Hist. (12) 6: 194-195. 
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