394 Mr. G. W. Kirkaldy oi the 
whereas, in the Notonectidze at least, any other method 
is of little avail; moreover, the majority of the types are 
lost, and it is apparently impossible to appropriate the 
descriptions with any degree of certainty. 
Since then, little has been done; a few species have 
been described at intervals, and three new genera, viz. : 
—Antipalocoris, Scott,' Martarega, B. White,? and 
Signoretiella, Berg,® each with a single species. 
Before proceeding, | must express my thanks to the 
friends and correspondents who have lent or given me 
types or other specimens, and otherwise assisted me; as 
these include nearly all the entomologists who are in- 
terested in Rhynchota, it is impossible even to enumerate 
them. I am particularly indebted to Professors Uhler 
and Montandon, to M. Maurice Noualhier and Mr. 
Edward Saunders ; also to the directors and assistants 
of the British, Budapesth, Hamburg, Hope (Oxford), 
Paris, Stockholm, and Vienna Muscums. 
Fam. NOTONECTIDA. 
Rostrum 3-4 segmentatum; antenne 4-segmentate ; pro- 
noti margine postica pedes antici inserti; scutellum 
magnwne. 
The insertion of the anterior pedes on the posterior 
margin of the pronotum at once separates the Notonec- 
tide and Corixidve from all the other aquatic pagiopodous 
Rhynchota, in which the insertion is on or near the 
anterior margin; the visibility and size of the scutellum 
distinguishes the Notonectide from all the Corixide, 
except Diaprepocoris, Kirk., from which, however (and 
from the other Corixide), they are readily differentiated 
by the three- to four-segmentate rostrum; the anterior 
tarsi, moreover, are quite differently shaped in these two 
families, being simple and raptorial in Notonectida, 
while in Corixidze they are more or less dilated and 
spoon-shaped. 
T'wo subfamilies are embraced :— 
1 (2) Tibie postice tarsique postici ciliati; venter cari- 
natus, ciliatus ; rostrum 4-segmentatum ; oculi 
permagni, conspicni. ‘ . NOTONECTINA. 
1 1872, in Marshall, Ent. Mo. Mag., viii, p. 244. 
? 1879, Trans. Ent. Soc. Lond., p. 271. 
3 1883, An. S. Cient. Argent., xvi., p. 122. 
