No. 34.] HEMIPTERA OF CONNECTICUT I NERTHRIDAE. 393 



of the form which by common consent is regarded as oculatus 

 Fabricius. This is the first key for species of Gelastocoris; and is 

 on a purely structural basis. Descriptions heretofore of the 

 species of this genus, as of other, waterbugs, have been by color 

 largely. In color, this group is singularly variable yet, paradox- 

 ically enough, quite similar. When one gets the general color 

 effect, it is characteristic for each species, but in every series of a 

 species there are examples which approach in color others in a 

 different species. The facies of Gelastocoris is also peculiar, but 

 too elusive to put into words, as the peculiar or striking aspect of 

 a species depends on a "more or less" description. If all, or a 

 given species which has been used for comparison, are before a 

 worker, no difficulty presents itself. But if he has only a single 

 species, it is nearly impossible to determine it. Habitus is the key 

 to species, but habitus strictly controlled by structural characters, 

 many of which are still to be developed. No Gelastocoris seems as 

 yet to have been found in Connecticut, although there seems to be 

 no a priori reason for this failure. 



Key to Species. 



Front longer than broad. Eyes more prominent anteriorly and 

 markedly inclined in that direction. Explanate margin of corium 

 smooth, or at most imperceptibly wavy. Prominences on disk of 

 thorax strongly marked, disk tumid. Posterior three-fourths of 

 sides of pronotum rounded, convergent anteriorly, but not sub- 

 transverse. Anterior claws slightly longer than tarsus, tarsus 

 with claws one-fourth shorter than tibia. Second joint of pos- 

 terior tarsi nearly one-half longer than third. Mesosternal 

 tongue broad, short, oblique. Hemelytra not passing tip of abdo- 

 men, rounded at apex ; membrane reduced. Tubercles white on 

 a dark variegated ground, producing a distinct dark and white 

 clouding barberi n. sp. 



Front as long as broad. Eyes somewhat inclined anteriorly, more 

 prominent laterally. Explanate margin of corium crenulate. 

 Disk of prothorax flattened; discal prominences not marked and 

 somewhat linear in effect. Posterior three-fourths of sides of 

 pronotum subtransverse, rounded. Anterior claws shorter than 

 tarsus; tarsus with claws half as long as tibia. Second joint 

 of posterior tarsi about one-third longer than third. Mesosternal 

 tongue narrow, long, erect. Hemelytra passing extremity of 

 abdomen, narrowed at apex ; membrane normal. Tubercles white 

 on a prevailing clay-yellow ground, which is sometimes clouded 

 medially with black oculatus 



G. oculatus Fabricius. 



Ent. Syst. Suppl., 525, 1798. 



This is the species reputed to occur in the Atlantic States but so 

 far as the writer knows has not been taken as far north as New 

 Jersey. 

 G. barberi Bueno, n. sp. 



Front vertical, triangular, longer than broad, rounded at distal 

 end; head with eyes broader than long; eyes pedunculate, reni- 



