AQUATIC INSECTS IN NEW YORK STATE 



215 



Callibaetis skokiana n. sp. 



Plate 7 



Imago. Length of body 9-lOmm; expanse of wings 18-20mm; 

 length of setae, male 20mm, female 16mm. Ground color pale 

 flesh tint, tinged with yellow (more yellowish in the female) 

 marked, mottled and dotted with brown; antennae, legs and 

 setae white. 



Head pale brownish, with whitish margins; in the male, 

 occupied superiorly by the large turbinate superior portion of 

 the compound eyes, which are pale egg-yellow on their superior, 

 faceted surface, with paler margins, and which are as large as 

 all the remainder of the head; in the female the top of the head 

 is very flat, and is traversed b}^ two longitudinal, irregular, pale 

 brown bands, which are surrounded and separated b}^ whitish. 



Prothorax paler, thickly dotted with brownish color. Dorsum 

 of the mesothorax with a pale, longitudinal median suture, each 



Fig. 1 Wings of Callibaetis skokiana, male 



side of which is a band of brown rounded off posteriorly, and at 

 the sides there are brown spots inferiorly. The median narrow 

 pale line is continued posteriorly to the abdomen, and there are 

 brown spots on the sides of the metanotum. Sides of thorax 

 irregularly speckled with brown. Legs white with darker mark- 

 ings at the knees and at the ends of the tarsal segments, the 

 last one of which is wholly washed with brown. Wings with 

 the usual costal band, differing in the sexes, behind which they 

 are hyaline. The band in the female is darker and better de- 

 veloped. It covers proximally the bases of all the veins and is 

 regularly narrowed to the apex, ending just before the apex of 

 the wing, not lobed posteriorly, fenestrate with hyaline on most 

 of the cross veins except toward the base, and reduced to a yel- 

 lowish wash in the stigmatic region and about the humeral 

 cross vein. In the male the costal fascia is paler, and usually 

 disappears just before the yellowish stigmatic space, which is 

 sometimes filled with anastomosing cross veins. The venation 

 of the male is shown in figure 1. There is much variabilitv in the 



