THE CANADIAN ENTOMOLOGIST 255 



The nymph has conspicuous lateral expansions to the segments 

 of the abdomen and has prominent mid-ventral meso- and meta- 

 thoracic spines. Gills on segments 1-7 and all single. The terminal 

 segments of the labial and maxillary palpi pointed and the lateral 

 lobes of the hypopharynx rounded. 



Siphlonisca aerodromia Needham. 



The description given in Bull. 134 N. Y. State Mus. errs in 

 two minor points, namely, the claws of the fore leg of the female 

 are normal, i.e., similar to those on the other legs, and there is a 

 metathoracic mid-ventral spine as well as a mesothoracic one. 



Nymph. — Length 19-20 mm.; setae 8-9 mm.; legs 4.5 mm. 

 General colour a dark brown. Antennae longer than head, light in 

 colour, but terminal joint tipped with dark brown. Mouth-parts, 

 see PI. IX, fig. 1-5. Thorax darker above. Prominent mid- 

 ventral meso-and metathoracic "spines. Legs comparatively short 

 and stout. Tarsi and tibiae of about equal length. Abdomen dark 

 brown dorsally, tending to be darker along median line and along 

 a line just inside the line of gills. Segments 5-9 greatly expanded 

 laterally and each expansion produced backward into a spine. 

 Two longitudinal lateral dark brown lines on ventral surface. 

 Gills on segments 1-7 and all single, see PI. IX, fig. 1-5. Three 

 setae, the middle one very slightly shorter than the outer ones, 

 which are fringed on the inner sides only. Setae brown, but with 

 white tips. 



Ecological Notes. — The following are Mr. Alexander's notes in 

 regard to this species: 



"The type specimen, a female, was taken on June 6, 1908, 

 on rank vegetation at the south end of Sport Island in the Sacandaga 

 River. Careful search on that day failed to locate other specimens." 



"On June 6, 1909, at 5.20 p.m., there were scores of specimens 

 flying over the bridge, several of these were in copulation and a 

 large series of both sexes were taken. As it grew dark, the insects 

 mounted higher in the air. At dusk the species could be dis- 

 tinguished high up in the air by the remarkable breadth of the 

 abdomen. It is probable that the type taken in 1908 was the last 



