464 Osten Sacken: on the characters of the ihree divisions of 



Brauer's detinition tlie licad of the larva of Chironomns is merely 

 what he calls a „Kicferkapsel" and not a real head (Kopf). It follovvs 

 furtlier that Chironomns does not belong to Brauer's division Eu- 

 cephala. If Chironomi, their exserted larval head notwithstanding, 

 are not ItJncephata Brauer, wliat are JEucephalaf Is it probable 

 that Culicidae are Eucephala, vvhile Chironomidae are not? That 

 Cidecü, Corethra and Chironomns are closely allied genera, nobody 

 will deny; and yet, the mode of development of the imago within the 

 larva, as MM. M. & H. have shown (1. c. p. 274—275) is quite diffe- 

 rent in each of these genera. Here therefore the relationship is 

 patent in the imagos and disguised in the larvae. These anthors 

 further say (p. 276): „As a mere matter of dimensions such a head 

 „as that of the male fly of Chironomns could not be developed 

 „within the larval head. This explanation at once provokes a further 

 „question: why should any such disproportion exist between the head 

 „of the fly and that of the larva? We may say in reply that the fly 

 „is a nimble aerial insect, requiring keen senses and some degree of 

 „intelligence that it may escape danger, find a mate, and lay its eggs 

 „in a suitable position. The larva (of Chironomns), on the contrary, 

 „is an animal of very simple mode of life, feeding upon dead vege- 

 „table matter at the bottom of dark and slow streams. The abundance 

 „of its food, and the ease with which it can be appropriated, have 

 „led in this, as in many other cases, to some degree of degeneration, 

 „which is particularly apparent in the larval limbs and head." 



These results tally exactly with what I asserted in my „Suggestions" 

 (1. c. p. 31): first, that the divisional character borrovved by Brauer 

 from the head of the larva was an uncertain one, and second that 

 better results might be obtained by beginning the inquiry with the 

 imago, especially with the organs of orientation about the head. 

 I said verbatim that Brauer's groupings did not succeed because 

 they were „principally based upon a character of subordinate value, 

 „taken from the wings, and on another character of doubtful im- 

 „portanco, borrowed from the larvae, without sufficient regard for 

 „the Organization and the affinities of the imagos. I believe that a 

 „natural arrangement must be the result of the study of those organs 

 „of the imago, which are necessary for the functions of external life, 

 „principally therefore of the organs of orientation connected with the 

 „head (eyes and antennae), and in the second line, of the organs of 

 „locomotion (legs and wings)." 



In his reply to my „Suggestions" (in the Sitzungsberichte of the 

 Vienna Zool. Bot. Ges. 6 May 1891) Brauer deplores „den unglaub- 

 lichen IiTthum einiger Entomographen, dass die Larven keine Be- 



