NOTONECTA. 369 
Mexico!479 (Mus. Berol.§, Sallé), San Luis Potosi (Dr. Palmer), Pinos Altos in 
Chihuahua (Buchan-Hepburn), Amula in Guerrero (H. H. Smith), Jalapa (Hoge), 
Oaxaca (Sallé, in Mus. Brit.3); Guarumaua, near the city (Champion); Costa Rica’, 
Rio Sucio (Rogers) ; Panama (Boucard).—Cotomsta?. 
A very variable and common insect in’ Central America. It is easily distinguishable 
by the very large eyes, which are narrowly separated behind, the blackish vitta on the 
underside of the femora and trochanters, and the smooth and thickened median carina 
of the fourth ventral segment. The females have this segment elongate, the apex of 
the sixth produced into a long process in the middle, and the apex of the fifth also 
slightly produced in the centre. The males have an additional ventral segment *, the 
fourth not longer than the sixth, and the seventh narrowly produced and subtruncate 
at the tip. The specimens from Jalapa (with one exception) and all those from 
Guatemala southwards have the anterior angles of the pronotum more or less 
rounded, instead of acute and slightly deflexed, as in the type; but as intermediate 
forms occur, very little value can be placed on this character. The females, it may be 
noted, often have the sides of the pronotum more sinuous than the males. Mr. Rogers 
sent us a large number of specimens of this species from Costa Rica. 
One of the types of WV. klugii, Fieb., belonging to the Berlin Museum, has been 
examined. We give figures of the ventral segments of both sexes—6 b(¢),7(2); 
also of the genitalia of the male, opened (6 ¢), and of the antenna (6 @). 
2. Notonecta montezuma. (Tab. XXII. figg. 8, 8a, ¢; 9, 2.) 
Notonecta montezuma, Kirk. Trans. Ent. Scc. Lond. 1897, p. 402°. 
Hab. Mexico f (Coffin, in Mus. Oxon.'). 
Very like WV. mexicana, and agreeing with it in having a dark vitta on the underside 
of the intermediate and posterior femora and trochanters, but differing from that insect 
in its much more elongate shape; the eyes also are a little smaller and less convex, 
the interocular space is more deeply sulcate laterally on the vertex, the ventral carina 
in both sexes is smooth and thickened down the entire length of the fourth and fifth 
segments, and there is a smooth space down the centre of the following segment. 
None of these last-inentioned characters are noticed in the description’. The types, 
g @, have been examined. The North-American WV. insulata, Kirby, said by 
Prof. Uhler to occur in Mexico, and of which I have seen a specimen determined by 
Mr. Kirkaldy, is a nearly allied form, with the posterior femora and trochanters also 
vittate beneath ; but it differs from 1. montezuma in having the eyes less approximate 
behind and the ventral carina thickened along the fourth segment only. 
* Apart from the visible convex genital segment. 
+ Prof. Poulton informs me that the locality is not ‘“* W. Mexico,” as stated, the “‘ W” on the label simply 
indicating that it was a Westwood specimen. 
BIOL. CENTR.-AMER., Rhynch., Vol. I1., February 1901. 47 
