822 Charles Paul Alexander 



The following descriptions of the immature stages are adapted from 

 those of Needham and Malloch: 



Larva. — Length , 10-15 mm. 

 Diameter, 1.5-2 mm. 



Coloration green, with distinct brown marks on dorsum and with an interrupted mid- 

 dorsal row of alternating paler dots and crossmarks; dark area made up of closely placed 

 spinous hairs, clear areas for the most part devoid of hairs. 



Body cylindrical, abruptly tapering behind on last abdominal segment. Legs lacking, but 

 a scurfy, pubescent creeping-fold on under .surface of meso- and metathorax, a similar one on 

 first abdominal segment, and much larger, transversely placed, fusiform creeping-ridges on 

 ventral surface of abdominal segments 2 to 7, on anterior ring of each .segment. Incisions 

 between dorsal segments of abdomen margined with blackish spinules, which are slightly 

 stronger than other hairs of dorsum. Spiracular di.sk vertically cleft, with sloping sides, 

 folded together when under water, border of aperture fringed with short hairs and destitute 

 of fleshy lobes. Spiracles oval. Anal gills four, fleshy. 



Head large, similar in general appearance to that of Limnobia, entirely retractile within 

 enlarged prothorax; head showing a broad, pale yellow, median band, sides black from base 

 of antennae backward. Ivabrum transversely oval, with a margin of close-set, scurfy hairs; 

 clypeus one-fourth broader than labrum, yellow, with parallel sides but emarginate on front 

 for reception of labrum; three recurved, stout setae on lateral margin of clypeus on each side, 

 one on each angle and two on disk. Mentum slightly convex in outline, median tooth much 

 longer and stouter than first lateral, second and third laterals as large as median tooth. 

 Antenna long, the shaft about three times as long as its greatest diameter. Maxillary palpi 

 short and inconspicuous. 



Pupa. — Length, 8-9 mm. 

 Diameter, 1.5 mm. 



Body smooth and shiny, ends brownish. Front of thorax upcurved dorsally. Pronotal 

 breathing horns broad, laterally flattened, obtuse at apex, each with a basal recurved, sharp 

 hook on its dorsal side; breathing tubercles arranged in a semicircular row along obtuse tip 

 of horns. Dorsum of thorax with a faint fretwork of raised lines on surface. Abdomen 

 smooth, with transverse lines of scurfy pubescence, terminating in a pair of stout, sharply 

 recurved hooks. 



Malloch (1915-17 b, pi. 33, fig. 5) has figured the peculiar pronotal 

 breathing horn of this species. 



Dicranomyia stulla O. S. 



1859 Dicranomyia stulla O. S. Proc. Acad. Nat. Sci. Phila., p. 210. 



Adults of Dicranortiyia stulta are often exceedingly abundant, flying 

 about, or resting in close proximity to, rocky ledges or cliffs near streams. 

 They are found commonly in June, associated with such crane-fly species 



