No. 34-] HEMIPTERA OF CONNECTICUT: VELIIDAE. 417 



Velia Latreille. 



The genus Velia is represented in the Atlantic States by only 

 two species, neither of which is known as yet from further north 

 than the vicinity of Washington, D. C. Aside from the fact 

 that they are semi-aquatic, little seems to be known in regard to 

 these insects. Miall limits his remarks on the European Velia 

 currens to stating that it swims under water more readily than 

 Gerris and walks back downward on the surface film. The genus 

 is dimorphic as to wings which of course makes certain structural 

 changes in the thorax. Like all their congeners, the species of 

 the genus are predaceous.* So far as known, they are stream 

 forms, as denoted by the names of the two Europeans, currens and 

 rivulorum. These two congregate in small schools, but this can 

 scarcely be the habit of our own forms, as they have been taken 

 only by ones and twos. The European species overwinter as 

 adults in moss on stones. The eggs are deposited in spring on 

 the vegetation coming to the surface.f 



The species thus far recognized from the Eastern United States 

 may be separated as follows : 



Key to Species. 



Intermediate tarsi subequal to or but little longer than posterior, 

 second and third joints subequal ; second joint of hind tarsi longer 

 than third stagnalis 



Intermediate tarsi much longer than posterior, second joint much 

 longer than third; second joint of hind tarsi shorter than third; 

 (first joint of antennae nearly one and a half times as long as 

 second) australis 



V. australis Bueno. 



Bull. Brook. Ent. Soc, xi, 54, 1916. 

 V. stagnalis Burmeister. 



Handbuch d'Ent, ii, 212, 1835. 



Rhagovelia Mayr. 



Rhagovelia, next to Rheumatohates, is perhaps the most interest- 

 ing genus of the water striders in regard to very special adaptation 

 to a peculiar habitat. In nature, I know two species, our own 

 North American Rhagovelia obesa, and a Rhagovelia from Mexico, 

 both of which are found only in running streams. The unique 

 cleft intermediate tarsus and the swimming plume arising there- 

 from are peculiarly suited to the insect's constant striving against 

 strong currents. The species of this genus are dimorphic, but in 

 our latitude the fully winged forms are rarely seen. Little is 

 known as to their breeding habits or other phases of life. The 



*A. Griffini, Gli Insetti Acquaioli. 1894. 



t C. Wesenberg-Lund, Fortpflanzungsverhaltnisse : Paarung und Eiablage 

 der Susswasserinsekten. Forts Nat. Forsch. Halle vii, 196, 6. 



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