268 INSECT TRANSFORMATION 



Trias of Germany, is definitely referable to the megalopteroid 

 division (alder-fly and snake-fly group) of the Neuroptera ; 

 and Archepsychops and Protopsychopsis, from the Upper 

 Trias of Queensland, belong to the planipennian (lacewing 

 and ant-lion division) of the same order. These divisions are 

 both represented by fossils preserved in rocks of later age 

 Jurassic, Cretaceous, Tertiary and are probably less prominent 

 in the insect fauna of to-day than they were in that of the 

 Mesozoic or Secondary life-era. The Mecoptera (scorpion- 

 flies), also represented by fossils of Triassic age, pass on with 

 comparatively slight modification to our own day, in which, 

 however, the few existing families are clearly the survivors 

 of an assemblage more dominant in Mesozoic times. These 

 two orders, the Mecoptera and Neuroptera, must, therefore, 

 be regarded as relatively ancient and primitive. 



The Paramecoptera (Belmontia of the Australian Permian) 

 are not only recognizable as nearly collateral with the Neurop- 

 tera ; in their nervuration they show a condition from which 

 both that of the Trichoptera (caddis-flies) and that of the 

 Lepidoptera (moths and butterflies) can be directly derived, 

 so that they have been reasonably claimed as ancestral to 

 those two orders, whose rather close relationship to each 

 other has been recognized by all modern students of insects. 

 The oldest known caddis-flies are the Necrotauliidae from the 

 European Lias (Lower Jurassic), to which the existing Rhyaco- 

 philidae are nearly akin. The evidence of fossils shows, 

 therefore, that the Trichoptera are later in origin than the 

 primitive neuropteroid insects, and it has been pointed out 

 (pp. 122-3) now the caddis larva is modified, in accordance 

 with its water-dwelling, case-building habit from the campodei- 

 form type. The Lepidoptera, with their highly-specialized 

 sucking mouth-parts, are a more advanced order than the 

 Trichoptera, and their oldest-known fossil representatives are 

 an Upper Jurassic family, the Palaeontinidae, preserved in 

 English and German rocks. These appear to be collateral 

 with our two existing sub-orders the Homoneura and 

 Heteroneura (see pp. 184-5) but ancestral to neither; probably 

 the earliest Lepidoptera (Homoneura) were Liassic in age, 

 and their fossil remains are still unknown. Comparing the 

 early stages of Trichoptera and Lepidoptera, it is remarkable 



