Diptera: Nemocera vera, N. anomala and Eremochaeta, 445 



£,imnobina breathe through tlie posterior spiracles; but manj' other 

 larvae have tracheal branchiae. The retractile processes which I 

 observed in an aquatic Tipulid larva in North-America I recognized 

 as branchial (0. S. Studies etc. II, p. 166; Berl. Ent. Z. 1887); they 

 resemble the processes figured by Reaumur IV, Tab. 14, f. 10. 

 Similar processes are described by Beling on the larva of Pedicia 

 rivosa, Verb. Zool. Bot. Ges. 1878, p. 45, and by Prof. Mi all on that 

 of Dicranota (Miall, in litt.). The plumed appendages as the end 

 oi ElUptera omissa (Mik, Wien. Entom. Zeitscbr. 1886, p. 340) and 

 those on the larva oi LimnopMla fuscipennis described by Beling 

 and figured by Brauer (Vienna Denkschr. etc. Vol. 47, 1883, Tab. I, 

 f. 6) are evidently branchiae. The two short projecting lobes at the base 

 of the breathing-tube of Ptychoptera Grobben (Vienna, Sitzungsber. 

 etc. 1875,) calls branchial appendages. Such are also to all appearances 

 the filaments issuing from different parts of De Geer's aquatic larva 

 of Phalacrocera replicata, the use of which has not been investi- 

 gated yet. 



In most of the larvae of the Nemocera the head is free, that 

 is, not imbedded in the skin of the thorax; the Tipididae alone 

 have it imbedded. But among the Tipulidae the genus Ptychoptera 

 form s an exception, and has a protruding head, like the other Ne- 

 mocera. Being protruded, the head of Ptychoptera is provided with 

 a chitinous covering of a stronger consistency than the heads of the 

 other larvae of Tipulidae, which being imbedded, are protected by 

 the thick larval skin. In other respects both kind of heads are 

 horaologous; the parts of the mouth have the same structure (compare 

 the figure by Brauer in bis Z. K. M. III, Tab. II, f. 19), and the 

 dentate mentum, characteristic of the Tipulidae, is present in both. 

 The Separation of the Ptychopterina from the Tipididae by Brauer 

 has no foundation, neither in the structure of the larva, nor of the 

 Imago, as I have already shown in my „Studies on Tipulidae" (Berl. 

 Ent. Zeitscbr. 1887, p. 227). 



I may add that the general statement of Brauer about the Po- 

 sition of the cephalic ganglion within the head of bis eucephalous 

 larvae, and outside of it in other larvae, as yet requires confirmation.i) 

 Prof. Miall, in bis recent article on the larvae of Chironomus 

 (Nature, Sep. 10, 1891, p. 458) distinctly says that their larval head 



i) „Der Bau der Cecidomyiden-Larven nähert sich nur dadurch 

 mehr den Ti'puliden (Polyneuren), weil bei beiden das Nervensystem 

 hinter der Kieferkapsel beginnt, während die Eucephalen einen Kopf 

 mit Ganglien zeigen." Brauer, Z. K. M. III, p. 10. — The same 

 Statement 1. c. p. 1. — Compare the Postscript. 



