1915] Nemocera Not a Natural Group of Diptera 97 
ferable to the creation of new terms, particularly as the defini- 
tion of those groups has been modified by different workers 
and as the names are appropriately applicable to the present 
groups. The status of these groups is now as follows: 
Oligoneura Polyneura 
Bibionide Psychodide 
Scatopsidee Culicidee 
Simuliidee Ptychopteridz 
Mycetophilidee Tipulide 
Sciaridze Rhyphideze 
Blepharoceride Orphnephilidz 
Chironomid 
Cecidomyidze 
Postscript.—Since the foregoing was written, Dr. E. P. 
Felt has called my attention to the possibility of the occurrence 
of metapneustic larvae among the Cecidomyide. The forms in 
question are the so-called resin gnats, recently referred by Kieffer 
to the genus Retinodiplosis,’ whose larve live in the resin 
exuding from the injured twigs of pines. Fortunately the 
larve of these forms have been studied and the necessary data 
were obtained, for Retinodiplosis resinicola O. S. in papers by 
Comstock’ and by Miss Eckel,’ and for R. resinicoloides Wil- 
liams in a paper by this last author. The facts disclosed are 
highly interesting. These larve are structurally peripneustic, 
but functionally they are metapneustic. The lateral spiracles 
are minute and not functional, being under normal conditions 
embedded in the resin, while the last pair (on the eighth ab- 
dominal segment) is much enlarged and modified for its aug- 
mented duty. / 
The position of the Blepharoceride, as indicated in the fore- 
going, is confirmed through definite information regarding the 
organization of the larval tracheal system. No mention of 
larval spiracles could be found in the more recent literature on 
the group, and this led to the inference that none occur. Ina 
recent paper Mr. Hugh Scott shows that in Paltostoma minute 
functionless spiracles occur on all six of the body segments of 
the larva” and that such spiracles were already demonstrated 
on the larva of Curupira by Fritz Mueller in his classic paper." 
Therefore the Blepharoceride unquestionably belong in a 
peripneustic Series (Oligoneura). 
