4(32 Osten Sacken: vn thc charaeters of t/ie three divisions of 



dift'er tVoni tlie others in having the convolutcd legs less closely sol- 

 dcred to tlic body of the thorax. I5ut still more important for me 

 was the fact that the pupa of Dixa (1. c. IV, 111) shows thc same 

 structure and comes nearest to the pupa of Anoplieles. D'xxa 

 and Anopheles, which differ in the imago-shape so mach, have thero- 

 fore very closely resembling lai'vae and pupae. 



Yet another important fact results from Westwood's Observa- 

 tion. In this convolution of the legs of the Cidicidae, Chironomi- 

 dae and Dixldae, we seem to have a good character for distingu- 

 ishing their pupae from those of the other families of Nemocera 

 Vera: Tipnlidae, Mycetox>hilidae and Cecidomyidae. These have 

 their pupal legs stretched out straight, appressed to each other, and 

 extended over the abdominal segments. Even the aquatic Tipulid 

 pupae share this character, for instance that of Phalacrocera repli- 

 cata, figured by De Geer, and that oi Ptychoptera. And this cha- 

 racter furnishes us a new proof that Ftychoptera is a true Tipulid 

 and has nothing to do with Cidicidae, as Brauer contended. In 

 the Cecidomyidae the legs of the pupa streich along the abdomen 

 the farthest (compare the ligures in Winnertz's monograph; or the 

 pupa of Cee. papaveris Laboulb., or of Lasioptera picta Meig., 

 figured byDufour, Mem. de Lille 1845; in the two latter cases the 

 legs nearly reach the tip of the abdomen.) 



There is an cxception however among the pupae of the Cliiro- 

 nomidae. The genus Ceratopogon, aberrant in so many respects 

 from the other genera of the family, has the legs of the pupa straight 

 (perhaps because they are shorter?). The terrestrial pupae of this 

 genus are so represented by Dufour, Perris, Heeger. Of the 

 aquatic pupae of Ceratopogon we have that of Gerke, which is not 

 quite distinct, but seems to have straight legs. The pupa figured by 

 Meinert (1. c. Tab. IV, f. 136) is represented from the back, so that 

 the legs are not visible. Comp, also Laboulbene, Ann. S. E. Fr. 

 T. IX, Tab. VII, f. 7. 



The pupae of the Psycliodidae have straight legs. Compare the 

 figures of Bouche, Curtis, Journ. Roy. Agric. Soc. Vol. X, 1850; 

 p. 403, Tab. V, fig. 48—50 excellent figures of the pupa in three po- 

 sitions); Perris, Ann. Sc. Nat. 1840, p. 346—48 (the pupa is that 

 of Psychoda; but the larva that of some muscid!). 



p. 442. Concerning the two groups of larvae of the Nemocera vera. 

 That the metapneustic System of tracheal breathing is originally de- 

 i-ived from the peripneustic is beautifully illustrated in Brauer's 

 description of the metapneustic larva of Chionea (Verh. Z. B. Ver. 

 1854, p. 614). The longitudinal tracheal trunks emit lateral branches 



