Diptera: Nemocera vera, N.anomcda and Eremocliaeta. 44:3 



the most remarkable resemblance to the larva of Rhyplms, and often 

 occurs together with it. Three trustworthy authors have describcd 

 the larva as ampliipneustic: Lyonet, Dufour and Perris. The 

 two hitter have found the larva together with that of Rhyphus, and 

 were Struck by their resemblance, althoiigh fuUy aware of the diffe- 

 rences. Winnertz;, who bred such larvae froni the flowing sap of 

 trees (see his Monogr. d. Pilzmücken, p. 668) did not notice their 

 peculiar structure and says nothing about it. The pupae of M. pal- 

 lipes figured by Lyonet and Dufour and described by Perris have 

 two rows of little spines on each of the abdominal segments; the 

 pupae of all the other MycetopMlidae, as far as known, have no 

 such spines, Pupae of Rhyphus have similar spines, but only a Single 

 row on each segmeut. i) If there is a real relationship between the 

 larvae of Mycetohia and Rhyphus, we have a right to expect a cor- 

 responding relationship among the imagos. But as this relationship 

 does not exist, this is a problem yet to solve.2) The larvae of the Ceci- 

 domyidae, as far as known, are also remarkable for the unity of 

 their type, which is different froni that of the MycetopMlidae. Be- 

 sides the nine pairs of spiracles, their peculiarity consists in the 

 structure of the head, only a small portion of which is chitinized ; the 

 peculiar breast-bone (spatula sternalis); the shagreened surface of 

 the skin, often provided with characteristic processes in the shape of 

 warts, pseudopods, and anal projections etc. A remarkable instance 

 of adaptation was described by me, in the larva of Diplosis resinicola 

 (Trans. Amer. Ent. Soc. III, p. 345, 1871) the imago of which, jud- 

 ging by the structure of its antennae, must be closely related to Di- 

 plosis pini De Geer. The larva of the latter forms a cocoon of resin? 

 while the larva of D. resinicola lives imbedded in a lump of resin, 

 exuded on the smaller limbs of young scrub-pines (Pinus inops). 

 I did not perceive any lateral spiracles on it; the two tracheal trunks 

 end in a double tube at the end of the body, by means of which the 

 larva breathes. It brings to mind a similar case among the Coleop- 

 tera, where the aquatic larva of Dytiscus, although peripneustic, ab- 

 sorbs the air through the last abdominal pair of spiracles. 



l) Weyenbergh, in his Varia Entomologica (in Tijdschr. v. Ent. 

 XVII, 1874, Tab. 9, fig. 10 gives a figure of the pupa of Mycetobia 

 independently of other authors; but he represents it erroneously with 

 a Single row of spiues. 



■i) And it is a very impoitant physiological problem to solvc for 

 the right understanding of the metamorphoses of diptera; a fine oppor- 

 tunity for a physiologist, skilled in dissecting, to render a great service to 

 science. It is astonishing that it has not been attenipted before. 



