G. C. Crampton.
Remarks on the Phylogeny and Interrelationships of Nematocerous Diptera.
Psyche 31:238-242, 1924.

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238 Psyche [October
REMARKS ON THE PHYLOGENY AND INTERRELA-
TIONSHIPS OF NEMATOCEROUS DIPTERA
Massachusetts Agricultural College, Amherst, Mass. During the course of an anatomical study of the Nemato- cerous Diptera, undertaken at the suggestion of Dr. C. P. Alexander, a number of interesting and important points con- cerning the interrelationships of these most primitive represen- tatives of the order Diptera, were brought to light, and I would present herewith a brief resume of the principal features sug- gested by this study. The accompanying diagram of the lines of Chironomoidea
i o n $ Itonididae blepharoceridae
Mycetophiloidea \, \, ?' Other Tipuloids \ .
Psychodidae Trichoceridae,;
. Anisopodidae
----- ..- ----- - --- .--
,<h$hopteridae
Bruchomyidae'- Tanyderidae
Protodiptera
Fig. 1.
Lines of descent of the Nematocerous Diptera. descent of the Nematocerous Diptera will serve to illustrate the interrelationships here indicated.
Among the most primitive Diptera known, are the Tany- deridse and Bruchomyidse. Alexander, 1920, lists the Brucho- myidse as a subfamily (Bruchomyinse) of the Tipuloid family Tanyderide, but it seems preferable to raise them to family rank, since they differ from the Tanyderidse in many important features.
The immediate ancestors of the Bruchomyidse and Tany- dreidse evidently had a common origin-possibly in a Proto-



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19241 Phylogeny and Interrelationships Nematocerous Diptera 239 dipteran stem represented by such forms as Austropsyche, etc., described by Tillyard, 1919.
The Bruchomyidse are very like the ancestors of the Psy- chodidse, which branched off from the Bruchomyid stem to follow their own isolated path of development. On account of
the isolated character of the Psychodidse, which differ from both the Tipuloid Nematocera (Pronematocera) and non- Tipuloid Nematocera (Eunematocera) the Psychodidse and their ancestral types, the Bruchomyidae, might possibly be grouped together as Paranematocera, composed of the super- family Psychodoidea but this point is of no particular importance in the present discussion.
The Tanyderidse are among the most primitive of the Tipuloid Nematocera, and have departed but little from the ancestral Dipteran stock, but they have developed modifica- tions of their own, and it would be impossible to derive the rest of the Tipuloid Nematocera from this family alone, although it is possible that the Tipuloid family Ptychopteridse branched off from the ancestral Tanyderid stem, as shown in Fig. 1. The Tipuloid subfamily Trichocerinse of Alexander, is here raised to family rank, because the Trichoceridse di,ffer markedly from the Anisopodidse (Rhyphidas) in which family they have usu- ally been placed. On the other hand, the Trichoceridse are very like the ancestors of the Anisopodidse, and apparently had a common origin with the Anisopodidae, from which common origin they have departed less than the Anisopodidse have. The ancestors of the Trichoceridse arose from the common stem giving rise to the Bruchomyidse and Tanyderidae, and it would be impossible to derive the Trichocerids from any known Bru- chomyid or Tanyderid. The rest of the Tipuloid Nematocera are of no particular interest in the study of the lines of develop- ment of the non-Tipuloid Nematocera, and need not be further considered here.
The Anisopodidse (Ryphidse) furnish the "key" group in tracing the phylogeny of the non-Tipuloid Nematocera) and it is a question as to whether the Anisopodidse are still to be con- sidered as true Tipuloid Nematocera, or whether they have progressed far enough toward the non-Tipuloid Nematocera



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240 Psyche October
to be classed with the latter.
At any rate, the Anisopodid~e are
extremely close to the actual ancestors of the rion-Tipdoid Nernatocera, which were possibly of some "post-hisopodid," but "pre-MycetophiUd" type intermediate between the Aniso- podidse and Mycetophilidse.
The Mycetopfiiloidea (i. ei MyeetaphiJidse, Mycetobiidse, Sciaridse, etc.) arose from the Anisopodidse themselves, or from forms extremely like the Anisopodidse, and it is extremely difficult to determine whether to group such amectant types as the Mycetobiidie with the Mycetophilidse, or with the Aniso- podiclse. I have raised the subfamily Mycetobiinse of Edwards, to the rank of a family, and have placed it among the Mycetophiloidea next to the Mycetophilidse, rather than to in- dude the Mycetobiinee in the family Anisopodidse as Edwards does.
The Sciaridae are rather primitive Mycetophiloids worthy of family rank, but I do not think that Malloch is justified in raising thfe Mycetophilid subfamily Platyurins~ to family rank, and there is even some question of the advisability of raising the Bolitophilinae to family rank.
The Itonididse (Cecidomyidsej might be included among the Mycetophiloidea. At any rfate, they arose from the Aniso- podid-like ancestors of the Mycetophiloids, and their line of development parallels that of the Mycetophiloidea remarkably closely, so that there can be no doubt that their closest relatives are the Mycetophiloids.
The Bibionoidea include the Bibionidee, Scatopaidffi, etc., and the Simuliidse may possibly be grouped in this &perfamily also. The Bibionoidea are very closely related to the Myceto- philoidea, and apparently arose from the Anisopodid-like an- cestors oå t-he Mycetophiloidea.
The genus Hesperinus (and Hesperodes also) has been much shuffled about, having been placed in the family Bibionidse by some, in the family Mycetophilidse by others, and Hesperinus has even been placed in a separate family, the Pachyneuridse, by certain European entomologists. Hesperinw, however, is so closely related to the Bibionid genus PUda, that if Plecia



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19x1 Phylogeny and Interrelationships Nematocerous Diptera 241 is retained in the family Bibionidse, then Hesperinus must be retained in the Bibionidse also.
The Simuliidse are extremely closely related to the Chiro- nomoid family Ceratopogonidse, and apparently represent a connecting group annectant between the Chironomoidea and Bibionoidea, with some suggestions of affinities with the Culi- coidea. The Simuliidse apparently branched off at or near the base of the Bibionoid stem.
The Chironomoidea include the Chironomidse and Cera- topogonidse, and possibly the Thaumaleidse (Orphnephilidse) also. The Ceratopogonidse branched off from the base of the Chironomoid stem, and have retained many characters sug- gestive of affinities with the Simuliidae and with the Culicoidea also. The Chironomoidea are so closely related to the Culicoidea that it might be preferable to include them in the superfamily Culicoidea, but for the sake of convenience, the Chironomoidea have been treated as a distinct superfamily in the phylogenetic tree shown in Fig. I.
The Culicoidea include the Dixidse, Culicidse, and Chaor- boridse, the latter being usually regarded as a Culicid subfamily, the Chaorborinse (Corethrinse). The Dixidse appear to be very close to the ancestral stock from which the Culicidse and Chaor- boridse were derived. The Culicoidea and their close relatives, the Chironomoidea, were apparently derived from ancestors very closely allied to the Anisopodid-like ancestors of the Bibio- noidea and Mycetophiloidea, so that these Anisopodid-like forms were the types from which the Mycetophiloid~, Bibionoids, Chironomoids and Culicoids were derived. The Blepharoceroidea, containing the single family Blepha- roceridse, represent an extremely isolated "compact" group whose affinities are very difficult to determine. Of the three Blepharocerid subfamilies Edwardsininse, Blepharocer-in=, and Deuterophlebinse, the Edwardsininse, represented by the genus Edwardsina, are the most primitive; but even with the help of Edwardsina, it is practically impossible to determine the closest affinities of the Blepharoceridse, for despite Edwardsina's prim- itiveness) it is extremely isolated, and is not approached at all closely by any Nematocera I have seen. I find in the Blepha-



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242 Psyche [OC tober
roceridse some slight indications of affinities with the Bibionoidea, and also some slight suggestions of resemblances to the Chiro- nomoidea and Culicoidea. The mouthparts of Edwardsina resemble those of the Tanyderids, and Dr. Alexander finds suggestions of affinities with the Tanyderids in the wings of Edwardsina; but the other structures of Edwardsina show no marked resemblance to the Tanyderids, so that it is preferable to group the Blepharocerids with the non-Tipuloid Nematocera provisionally, leaving the matter of their closer affinities until more data on the subject is available.
In brief, the Culicoidea; Chironomoidea, Bibionoidea and Mycetophiloidea were apparently descended from Anisopodid- like ancestors, which in turn lead to the ancestral Trichoceridse. These were derived from ancestors like those of the Bruchomyidse and Tanyderidse, which sprang from the common Protodipteran stem, represented by such forms as the fossil Protodipteron Austropyche. The latter is extremely Mecopteroid in nature, and beyond a doubt the Protodiptera arose from the Mecopt'era themselves, or from the immediate ancestors of the Mecoptera, and the Trichoptera also arose from tlhe same stock. These lines of development are joined by those of the Hymenoptera and Neuroptera as we trace them back to their ultimate source in the Protorthoptera, or in the common Protorthopteran-Proto- blattlid stem from which the insects above the Palsedicyoptera (i. e., the "Neopterygota") were derived. These in turn lead to the Palseodictyoptera, and tohe Palseodictyoptera together with t,he Odonotoi ds and Ephemeroids (i. e., the " Archipterygota") , were apparently derived from the Lepismatoid ancestors of the Pterygota in general.




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