DIPTERA. — NOTACANTHA. 529 
Fries also describes the molestations caused by these insects in Lap- 
land, whilst Pohl and Kollar have described a Brazilian species equally 
obnoxious. ‘These authors state that it is called a musquito by the 
Portuguese Brazilians ; in North America, however, as I learn from 
Mr. R. H. Lewis, it is distinguished from that insect, and known 
under the name of the Black Fly. 
The transformations of S. sericeum have been observed by Fries 
and Verdat ; they are aquatic, living on the stems of Phellandrium 
and Sium. The larve (fig. 126. 19.) are cylindric, rather slenderer 
in the middle of the body, with the head distinct, furnished in addition 
to the trophi, with two short antenne and two singular flabelliform ap- 
pendages; the thoracic part of the body has a thick conical and retractile 
tubercle beneath ; the extremity of the body has also several curved 
appendages ; the pupa (fig. 126. 20.) has on each side of the front of 
the sides of the thorax eight very long filiform appendages, arising in 
pairs analogous to the appendages of the pupa of Chironomus ; the 
posterior part of its body is enclosed in a semioval membranous cocoon 
attached to the plants and open in front * ; the imago is produced be- 
neath the surface of the water, its fine silky covering serving to repel 
the action of the water. ; 
The genus Aspistes is remarkable for having its short antenne cla- 
vate at the tips. Some account of its history is given by Meigen 
(vol. vi. p. 317.). 

The second general division of the first section of the Diptera is 
composed of species in which the antenne do not consist of a regular 
series of ordinary-sized joints ; and corresponds with the Brachocera of 
Macquart, after the removal of the Pupipara. It consists of the three 
stirpes Notacantha, Tanystoma, and Athericera ; the antenne of which 
are generally shorter than the head, having the terminal joints either 
articulated in an indistinct manner, or completely soldered together 
into a mass terminated by a seta, which has at its base one or two 
* From observations which M. V. Audouin has communicated to me as to the 
formation of this cocoon, it appears that it is at first formed entire by the larva, 
and that the upper end is afterwards eaten away as far as a, thickened arch pre- 
viously forméd; the object of this contrivance is evidently to allow the action of 
the water upon the long filaments of the pupa, which are thus shown to be air- 
tubes. 
VOL. II. MM 
