1879.] 307 [ Hagen. 
preserved in carbolic acid, still the difference in size is far too great 
to assume that the specimens could, by duly hardening, be reduced 
to half of the size. 
The differences between S. pictipes and S. piscicidium are the lack 
in the former of any fulvous pubescence of the thorax, the presence 
of ashy white spots in front of the thorax, the black trochanters of 
the front legs, the color of the femur, the black band of the tibia, 
and of the first joint of the middle and hind legs, and the white base 
of the second joint. 
Among the unnamed species in the collection of the Museum of 
Comparative Zoology is one from Illinois of nearly the same size, but 
otherwise different. All other described North American species are 
much smaller. 
Nothing*is known about the habits of S. pictipes; probably it is 
not as obnoxious in the mountains as its relation, the black-fly, other- 
wise it would have long ago drawn the attention of travellers by bites 
in proportion to its size much larger than those of the black-fly. 
The larvae, partly full grown, are 12 mm. in length, and do not 
differ from those described, as far as I am able to judge by the de- 
scriptions. The pupa is 6 mm. in length, and has on each side eight 
filaments, arising from a common root, just as the figures in Verdat, 
repeated in Osten-Sacken’s paper in Amer. Ent., 11, 229. The only 
species represented in the biological collection of the Museum, S. or- 
natum from Europe, has only four filaments on each side, just as fig- 
ured and reported by Fries, and therefore do not favor Osten-Sacken’s 
opinion that Verdat’s species is identical with S. ornatum. 
The pouch or case in which the pupa lives is 7-8 mm. long, and 
differs remarkably from all the described species. It forms a tube 
2 mm. wide at top, smaller at the base, of a very irregular and coarse 
network ; sometimes a thread is coiled around the tube in an irregu- 
lar manner. I can nowhere find mention of any network or threads 
making the pouch of one of the other described species. ‘The net- 
work is similar to that of some Tenthredinidae. A cluster of such 
pouches is fastened one near the other with the base on rocks, and 
imitates somewhat a small wasps’ nest. It is rather remarkable that 
young and mature larvae, pupae and imagos were found together at 
the same time on the same spot. 
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