PAN-PACIFIC ENTOMOLOGIST 
Vol. 55, No. 1, pp. 46-50 
A NEW SPECIES OF STRIDULIVELIA FROM MEXICO, AND A 
NEW SUBGENUS FROM MIDDLE AMERICA 
(HEMIPTERA: VELIIDAE) * 1 
John T. Polhemus 
3115 S. York, Englewood, CO 80110 
Hungerford (1929) proposed the new genus Stridulivelia (as a subgenus 
of Velio. ) to hold five new species of water striders from South America and 
one species from Middle America. The South American species all possess 
stridulatory mechanisms, but cinctipes (Champion), the Middle American 
species does not. Since then Drake and Harris (1938, 1941), Drake (1951, 
1957) and Drake and Menke (1962) have added six more species. Another 
new species is described below. 
I have examined all known species of Stridulivelia. Without exception 
they have numerous depressed hair-free round or elongate regions on var¬ 
ious parts of the thorax and abdomen and on the jugum of the head (see 
Fig. 1; also see plates 1 and 2 in Drake and Menke, 1962). These depressed 
areas contain numerous round flat-topped pegs in a rather regular array 
(Figs. 2-4). The function of these structures is not known; thin sections 
examined under high magnifications (optical microscope) did not reveal any 
significant innervation (Polhemus and Moran, unpublished), so a hypothe¬ 
sized function as sound or electromagnetic receptors is refuted. No other 
group of veliids possess these depressed areas in a similar arrangement on 
the body, therefore Polhemus (1976) proposed that Stridulivelia be given 
generic rank. 
Drake and Menke (1962) reviewed the Middle American and West Indian 
species of Stridulivelia. They pointed out that all Middle American species 
lack stridulatory structures. The West Indian species treated, tersa Drake 
and Harris from Trinidad, has a stridulatory mechanism, but Trinidad is 
zoogeographically part of South America. All South American species pos¬ 
sess stridulatory structures. Drake and Menke apparently did not notice 
that the middle tarsi of all Middle American species have blade-like claws 
and the down-curving arolium is shaped like a blade (Fig. 5), whereas all 
South American species have slender claws and slender arolia. These dif¬ 
ferences and the vicariance pattern indicate an independent development of 
these two faunal groups, therefore I propose Aenictovelia new subgenus 
[Ainiktos, Gr., enigmatic, and Velia; feminine] to hold the four Middle 
American species, i.e., cinctipes (Champion), expeixis Drake and Menke, 
pueblana Drake, and secerna new species and type of the subgenus. 
All specimens of the new species described below are in the Polhemus 
