INSECTA DIPTERA. 185 



Diptera, by which the opinion which regards them as cor- 

 responding to the posterior wings, is strengthened. 



The apex of the poiser forms a club-shaped process filled with air, 

 which in the larger dipterous insects is not crushed without an audible 

 sound. But this, as well as the removal of both the poisers, although 

 it may be effected on one side without any remarkable prejudicial conse- 

 quence, involves an immediate injury to the power of flight, and is inevi- 

 tably followed, within from six to eight hours, by death. The close con- 

 nexion of these organs with those of respiration explains this phenomenon. 

 Several Hymeuoptera, in which both hinder wings had been cut off, exhibited 

 a similar result. The author infers from this that the balancers of the 

 Diptera are metamorphosed posterior wings, and not merely rudiments of 

 them, but organs essential to locomotion and to life itself. 



Zetterstedt's ' Diptera Scandinaviee 3 is in regular course 

 of progress. In the year 1843 the Second Volume has 

 appeared, including the families of the Dolichopodse and 

 Syrphici. 



Macquart's ' Dipteres Exotiques' is concluded with the 

 third part of the Second Volume. 



TiPULARiyE. On the transformation of some Diptera of the division 

 of the Nernocerse, and on their systematic position, by Loew. (Eut. Zeit. 

 p. 27.) 



(1) The author observed the development of Ceratopogon lipunctatus, 

 Meig. The larva lives under the moist bark of trees, and in the fissures of 

 posts standing in water ; the nyrnpha exhibits what is very remarkable, viz. 

 that it remains in the last larval envelope. (2) Lasioptera and Sciara 

 present great similarity in their earlier conditions, and stand for the most 

 part in such near relationship with each other, that Sciara can only be 

 in its natural position next to Lasioptera. 



Macquart (Ann. de la Soc. Ent. de Fr. 2 ser. i, p. 59, pi. 3) has described 

 a new genns, Blepliaricera, which he is inclined to place near Auisomera, but 

 which appears to me to be more closely allied with Simulium. In the male 

 the eyes are joined. The proboscis is surpassed in length by a pointed 

 labrum. The legs are long and tender. The antennas about 16-joiuted, 

 with fine hairs anteriorly. The genus appears to be nearly allied to Asthenia, 

 Westw. (vide last Report, p. 257) (293 Eug. Trans.), if it be in fact 

 distinct from it. Bl. lim/npennis, Macq., is met with in the South of France, 

 in the valley of the Loire, in great abundance. 



Rondaui (ib. p. 263) has given a Monograph on the genus Hebetomus, 

 instituted by him in 1840, in a short memoir which appeared at Parma; and 



