166 THE UNIVERSITY SCIENCE BULLETIN. 



Plea striola Fieber, 1844. 



"Highly arched behind; wing covers pointed; forehead with brownish- 

 red median stripe; eyes black; hind half of closing suture brown. From 

 North America. 



"It is three-fourths lines long. Similar to the two preceding species, 

 but noticeably narrowed and pointed behind. Grayish yellow. Over the 

 front, a brownish-red median stripe. Eyes black. The entire dorsal sur- 

 face is unflecked. The wing covers behind the suture are much higher 

 arched than the other species. Posterior half of suture brown, darker 

 at the margins. Legs yellowish, last tarsal segment brown at the tip. 

 Femur dark brown at base. The sculpturing consists of an impressed 

 point in the middle of the five or six covered reticulations clearly visible 

 in the substance of the wing cover, a very short delicate seta arises from 

 each puncture, which is visible only on close observation." — Fieber in 

 Entomologische Monographien, 1844, pp. 18-19. 



Genus NOTONECTA L. 



"Head. Eyes not contiguous. Labrum attaining to about the middle 

 of the second rostral segment. Last segment of antenna shorter than 

 penultimate. 



"Thorax. Pronotum not very transverse. Alse present. Hemelytra 

 divided into clavus, corium and membrane. Scutellum large and almost 

 equal in length to the metanotum, except in N. mexicana, where it is only 

 about half its length. Hind femora not attaining to the apex of hemely- 

 tra. Posterior ambulacra practically contiguous. Intermediate am- 

 bulcara not nearly contiguous. 



"Abdomen. Median ventral carina of the abdomen is thickly pilose, 

 as are the lateral margins, thus forming a waterproof covered way over 

 the 'gutters' which lie, one on each side of the carina, for the conveyance 

 of air. The junctures of the connexival ventral segments are always 

 covered with short thick hair, and the scutellum and hemelytra are 

 generally clothed with short golden yellow pubescence. The sexes are 

 almost indistinguishable in size, form, colour and general appearance, 

 though, of course, the female, when full of mature ova, is dilated more 

 than at other times. They can be readily separated by an examination of 

 the last three or four abdominal ventral segments. These are horizontal 

 in the female, rounded and anteriorly excavated in the male." 



Specific characters suitable for diagnosis are difficult to find. Kirk- 

 aldy used head measurements. These were also employed by Bueno and 

 are used in the following tables. Color does not furnish a reliable 

 diagnostic character. Kirkaldy, in casting about for some specific char- 

 acters, said: 



"Great hopes were entertained by me that the male genitalia would 

 furnish a reliable diagnostic character, but in the few species {N. glauca, 

 N. lutea, N. irrorata and N unduJata) , of which suitable material was 

 available, these hopes have not been realized." 



The writer has examined the ovipositors of the females of most of the 

 species in America and finds considerable specific difference in some. He 

 is quite sure he could distinguish any one of the four species above men- 

 tioned from one of the gonapophyses of the female, alone. Whether Dr. 

 Kirkaldy studied them with the same care and discrimination that Dr. 

 Harry Knight has used with the Miridae remains to be seen. 



