NEUROPTEEA— TRICHOPTERA. 177 



ous larval cases from different regions of Europe, but especially from Au- 

 vergne in France; it is also proven by their abundance where we should 

 at first little look for them, in the Prussian amber, where, according to 

 Hagen, they are more numerous than any other group of insects, excepting 

 Diptera, and comprise more tlian half the Neuroptera and Pseudoneuroptera 

 combined. Twenty-five species have been described (by Hagen and Pic- 

 tet) and several others mentioned (by them and by Kolenati) from amber, 

 a large proportion belonging to the Hydropsychidte and especially to 

 Polycentropus, of which eleven species are described. 



Trichoptera are, however, by no means rare at Florissant, and, as 

 stated above, a single species has been described from western Colorado. 

 Indeed, the Neuroptera from the prolific lake bed of Florissant are made up 

 in large part of Trichoptera, of which many hundred specimens have been 

 obtained. The larger part of them, indeed, are indeterminable, but there 

 are about one hundred specimens which show the neuration of the wings or 

 other characteristic part with some distinctness ; and while all the remains 

 of perfect insects from the European rocks are referred to the single sub- 

 family of Phryganidse, at Florissant Limnophilidse, Leptoceridie, and espe- 

 cially Hydropsychidse, are also represented. The species of this last men- 

 tioned group are also much more prolific in individuals, and the preponder- 

 ance in species would be even more marked were we able to include here 

 all the species really found, since most of those which are too imperfect 

 to be brought forward evidently belong to this group. All these groups, 

 and indeed all the subfamilies of Trichoptera, are represented in the Prussian 

 amber. Hydropsychidse are by far the most numerous, as in our own 

 Tertiai'ies. Then follow in the order of abundance LeptoceridjB, Sericos- 

 tomidse, Phryganidse, Rhyacophilidfe and Hydroptilidse, and Limnophilidse, 

 the last having but one representative. 



While, as we have said, the bulk of the specimens of Neuroptera 

 found at Florissant belong to the caddis-flies, the specific variety of such as 

 will bear description is not quite so great, as 40 per cent of all belong 

 here ; but in relation to any one other large group the number of species 

 greatly preponderates, as the group next in size in point of species is the 

 Odonata, which has less than 20 per cent. It is not a little curious to 

 compare this statement with Pictet's concerning the amber caddis-flies: 

 "Of about one hundred and twenty Neuroptera examined by me sixty- 



TOL XIII 12 



