No. 64] DIPTERA OF CONNECTICUT : MORPHOLOGY 115 



eral; and by thus making this discussion of a broader and more 

 inchisive character, it is to be hoped that it may be of more value 

 than would be the case if it had been restricted to a description of the 

 external morphology of the Diptera of the Connecticut region alone. 



Phylogenetic Conclusions 



The tentative suggestions concerning the lines of descent and the 

 interrelations of the principal subdivisions of the order Diptera, of- 

 fered in the following discussion, are based upon a comparative study 

 of such features as the thoracic sclerites, male terminalia, etc., and 

 are made in the hope that in the happier days to come, when the 

 Avarring world returns once more to the more profitable pursuit of 

 scientific progress, the taxonomists may be induced to attack these 

 problems more intensively than has been the case in the past. 



The ancestors of the Diptera were very closely related to the 

 triassic fossil Anstopsyche superlja Tilly ard, and other so-called ''Par- 

 atrichoptera", which apparently represent merely a suborder of the 

 Mecoptera; and present day Mecoptera such as Nannochorista^ Bit- 

 tacus, etc., are strikingly like the ancestors of the Diptera in practical- 

 ly all of their morphological details. 



The nematocerous families Tanyderidae and Psychodidae (of 

 the subfamily Bruchomyinae), together with the Trichoceratidae, or 

 "Petauristidae" as they are now called,* and the Tipulidae, are the 

 nearest living representatives of the first Diptera to be evolved; and 

 they represent the principal centers about which the rest of the 

 Nematocera tend to group themselves. 



The families clustering about the Psychodidae may be grouped 

 in the section Psychodomorpha, which contains three principal super- 

 families. The first of these superfamilies, the Psychodoidea, con- 

 tains the families Psychodidae, Tanyderidae and Ptychopteridae or 

 "Liriopidae". The second superfamily, the Culicidoidea, contains the 

 families Dixidae, Culicidae, Nymphomyiidae, Chironomidae or "Ten- 

 dipedidae", Ceratopogonidae or "Heleidae", Orphnephilidae or 

 "Thaumaleidae", Simuliidae or "Melusinidae", etc. The third super- 

 family, the Blepharoceratoidea, which includes the Blepharoceratidae 

 (with Edwards'tna as its most primitive representative) and possibly 

 the Deuterophlebiidae also (although this family may prove to be 

 more closely related to the members of the second superfamily men- 

 tioned above), occupies an isolated position in the section Psychodo- 

 morpha, and its closest affinities have not as yet been definitely deter- 

 mined. 



The Tipulidae are related to both the psychodoid and the aniso- 

 podoid or ''phryneoid" groups of Nematocera (particularly to the 

 Tanyderidae and Ptychopteridae, the bruchomyine Psychodidae, and 

 the Trichoceratidae)', but their line of development is on a side branch 



* The less familiar family names substituted hy certain modern Dipterists for 

 the better known older names usually applied to the families of the Diptera, have 

 been indicated in quotation marks, since they are as yet unfamiliar to most of us 

 despite the fact that they may possibly eventually supercede the older names. 



