Vol. XXvi] ENTOMOLOGICAL NEWS. 437 



for the nymphs lire after the removal of the processes . 



(and) the skin of these processes is harder than is usual 

 in Insect gills." Similar views were also expressed by Hey- 

 «nons ( 1904, pp. 23, 24) : 



The exchange of gas during this period [youngest larval stages] u 

 accomplished without doubt not solely through the appendages, but in 

 a sufficient way through the entire body-surface which at first is cov- 

 ered with extremely delicate chitin During the larval period there 



can be no doubt that the three appendages have become primarily 

 breathing organs from the physiological standpoint But. as earlier. 

 the caiirc body-turface serves for retpiratioa in addition to the gill- 

 appcndngc* »nd a loss of the appendages in no way leads to death of 

 the animal 



Tillyard ( 1909, pp. 381-2). discussing the caudal appen- 

 dages of the larva of the Australian Diphiebia, while admitting 

 tlut "the presence of niunerous branched tracheae in these 

 gilb" mtist mean "that originally they were in some way or- 

 gans of respiration." points out that the loss of these gills 

 "<l(x's not affect the respiration of the insect in any way," and 

 doubts "whether even the wide lateral gills of DiphUbia, fed 

 by two large tracheae, are of any use at present for atixiliary 

 respiration." 



Rectal Respibation. CALOPnERvciNAE. 

 The earliest record of observations on rectal respiration in 

 this group appears to be that of Roesel von Rosenhof ( 1749. 

 p. 43) when he aajrs of the nymphs (of Caloptrryx] that they 

 draw "their air not through the nH>uth. but through the abdo- 

 men, and such can easily be perceived in them if they are kept 

 m a dear glass full of %vater." I^four ( 1852. p. 91 ) saw 

 larvae of Caloptrrix "swallow through the anus the water 

 wlach serves for their respiration." He described ( 1849. 1852. 

 p. 87) gills in the rectum as forming three membranous folds 

 ("raquettes") fixed by a single extremity to the inner and 

 posterior part of the stercoral iKxrket in such manner as to be 

 free and floating for tvi*o-thirds of their length. Hagen (i88oa, 

 p. 160) found these gills "genau wie Leon Dufour." This 

 statement was called forth by Olga Poletaiew's denial ( 1880, p. 

 450) of the existence of rectal gills in the larva of Calopteryx 



