THE SMALLER WATER STRIDERS. 989 



KEY TO EASTERN SPECIES OF MIOROVELIA. 



a. Antennae equal to or shorter than head and thorax united; abdomen 

 of wingless form without silvery pubescence. 

 b. Antennae shorter than head and thorax united; hind tibiae curved in 

 male; pronotum, wingless form, with a transverse linear im- 

 pression before the middle; male elongate, fusiform, female or- 

 bicular (fig. 198, a and b) . 1125. borealis. 

 bb. Antennae subequal in length to head and thorax united; hind tibiae 

 straight in both sexes; pronotum without the linear impression; 

 sexes quite similar in form. 

 c. Color sooty black; wingless form with pronotum produced back- 

 ward to second dorsal and minute white elytral pads present; 

 length, 1.6 — 2 mm. 1126. atrata. 

 cc. Color pale to dark brown; wingless form with pronotum not pro- 

 duced backward, reaching at most the base of first dorsal and 

 elytra wholly absent. 

 d. Fourth antennal but slightly shorter than width of interocular 

 area, more than twice as long as second; mesonotum visible; 

 length, 1.3 — 1.6 mm. 1127. hinei. 

 dd. Fourth antennal but little more than half as long as width of 

 interocular area, but little longer than second; mesonotum 

 not visible; length, 1.5 — 1.8 mm. 1128. austrina. 

 aa. Antennae longer than head and thorax united; abdomen of wingless 

 form often with silvery pubescence. 

 e. Joint 1 of antennae shorter than 3, 4 subequal to 2 and 3 united; 

 elytra with several white spots; wingless form shining, almost 

 smooth; length, 2.3 mm. 1129. albonotata. 

 ee. Joints 1 and 3 of antennae subequal in length; wingless forms pu- 

 bescent, opaque. 

 /. Joint 4 of antennae slightly longer than 2 and 3 united; abdomen 

 and connexivum of wingless form with conspicuous tufts of 

 silvery pubescence; length, 1.7 mm. 1130. buenoi. 

 ff. Joint 4 of antennae much shorter than 2 and 3 united ; length, 

 2 — 2.3 mm. 

 g. Wingless form with mesonotum concealed by pronotum; dorsum 

 of abdomen with patches of fine bluish-gray pubescence on 

 base and apex; winged form unknown. 1131. fontinalis. 

 gg. Wingless form with mesonotum visible; dorsum of abdomen, but 

 not the connexivum, with conspicuous patches of silvery-gray 

 pubescence; elytra of winged form brown, unicolorous or 

 nearly so. 1132. Americana. 



1125 (1303). Microvelia borealis Bueno, 1916a, 59. 



Winged form — Elongate, slender, subfusiform, male; broader, sub- 

 orbicular, female. Head and pronotum dark velvety-brown, the former 

 with a streak of silvery pubescence next the eyes; elytra fuscous, the 

 cells grayish, the apical one with a whitish stripe; base of first antennal, 

 a transverse spot on front margin of pronotum, prosternum, coxae, basal 

 half of femora and middle of abdomen, dull yellow; remainder of under 



