432 Osten Sacken: on the characters of the tliree divisions of 



timcs, as I said abovc, the developmcnt of tlic cyes is such that tliey 

 invade nearly the whole hcad. I do not find such a conformation 

 explicitly mcntioned in any description; it is probably iuvolved in 

 such expressions as contiguous and broadly conti guous. I des- 

 cribed such a development in Diplosis resinicola c/ Q , which I 

 bved from accumulations of resin on pine-trees in the State of Nevv- 

 York (0. S. Trans. Am. Ent. Soc. Vol. III, p. 346, 1871). In this 

 case the eyes, coalescent above and below the antennae, occupy in 

 both sexes nearly the whole upper side of the head, without any su- 

 ture, and leave only a small space for the Insertion of the antennae. 

 As exceptions among the Cecidomyiae may be quoted Heteropeza 

 and Miastor in which the slightly lunate eyes are separated by a 

 broad front in both sexes (compare Winnertz Stett. Ent. Z. 1846, 

 p. 13, Tab. I and N. Wagner 's figures in bis large folio on Paedoge- 

 nesis, Kazan 1862). In a Campylomyza which I examined alive, the 

 lunate eyes were in contact above the front, but a suture was dis- 

 tinctly visible. 



The Cidicidae and Chironomidae have lunate eyes, oftcn in 

 contact above the front and sometimes also below the antennae, The 

 excessive development of the eyes,. contiguous on the front and inva- 

 ding nearly the whole head, also occurs here; I have observed it es- 

 pecially among Ceratopogons with pubescent wings. I do not find 

 such structures described by Winnertz, and the only published instance 

 I can discover is the Cuban genus Oecacta, described and figured 

 by Poey, Memorias etc. 1851 I, p. 236, Fab. 27. This is the blood- 

 thirsty midge, well known in tropical Spanish America under the 

 dreaded name of „Jejen". The coalescence of the eyes here is com- 

 plete above and below the antennae, and the figure shows no trace 

 of a suture („la cabeza esta cubierta casi del todo por los ojos", says 

 Poey). The question is vvhether this figure is correct. In the Cera- 

 topoffons with lunate, contiguous eyes I have been able to distinguish 

 a slight suture. 



In the Mycetojjhilidae the eyes are generally separated by a 

 broad front, and lunate eyes are rare. Sciara alone has deeply lu- 

 nate eyes, the upper ends of which are either approximate, or cven 

 in complete contact above the antennae, but not confluent as in the 

 Cecidomyiae; in the cases observed by nie I could see the suture. 

 The group of Diadocidia, Mycetohia and Plesiastina have distinctly 

 lunate eyes, approximate on the front; a large Platyura from New 

 Zealand which I have examined has the upper end of each eye pro- 

 longed in a narrow strip, thus Coming in contact with a similar Pro- 

 longation of the opposite eye. In the Brazilian genus Platyroptilon 



